feat(settings): Frontend changes to support billing

Settings:
- Introduced billing enabled toggle with printer kill switch functionality in the settings.
- Added finance monthly budget reset day and timezone settings.

Other:
- Added cost center fields to PrintModal (if enabled)
- Switched sequence in PrintModal (cost center after estimated cost, and before print options)
- Implemented Finance Page

frontend/src/App.tsx

@@ -7,6 +7,7 @@ import { ArchivesPage } from './pages/ArchivesPage';
 import { QueuePage } from './pages/QueuePage';
 import { StatsPage } from './pages/StatsPage';
 import { SettingsPage } from './pages/SettingsPage';
+import { FinancePage } from './pages/FinancePage';
 import { ProfilesPage } from './pages/ProfilesPage';
 import { MaintenancePage } from './pages/MaintenancePage';
 import { ProjectsPage } from './pages/ProjectsPage';
@@ -199,6 +200,7 @@ function App() {
                   <Route path="queue" element={<QueuePage />} />
                   <Route path="stats" element={<StatsPage />} />
                   <Route path="profiles" element={<ProfilesPage />} />
+                  <Route path="finance" element={<PermissionRoute permission="cost_centers:read_own"><FinancePage /></PermissionRoute>} />
                   <Route path="maintenance" element={<MaintenancePage />} />
                   <Route path="projects" element={<ProjectsPage />} />
                   <Route path="projects/:id" element={<ProjectDetailPage />} />

frontend/src/api/client.ts

@@ -1185,6 +1185,11 @@ export interface AppSettings {
   // Staggered batch start defaults
   stagger_group_size: number;
   stagger_interval_minutes: number;
+  // Finance budget reset window
+  billing_enabled: boolean;
+  printer_kill_switch_enabled: boolean;
+  finance_budget_reset_day: number;
+  finance_budget_reset_timezone: string;
   // Plate-clear confirmation
   require_plate_clear: boolean;
   // Shortest job first scheduling
@@ -1897,6 +1902,8 @@ export interface PrintQueueItem {
   // Either archive_id OR library_file_id must be set (archive created at print start)
   archive_id: number | null;
   library_file_id: number | null;
+  cost_center_id: number | null;
+  estimated_cost: number | null;
   position: number;
   scheduled_time: string | null;
   require_previous_success: boolean;
@@ -2002,16 +2009,8 @@ export interface PrintQueueItemCreate {
   batch_id?: number | null;
   // Project to associate the resulting archive with
   project_id?: number;
-}
-
-export interface PrintBatchCreate {
-  name: string;
-  archive_id?: number | null;
-  library_file_id?: number | null;
-  /** When set, the listed pending items are assigned to the new batch
-   *  (manual "Group as batch"). When omitted/empty, an empty batch is
-   *  returned so the client can pass batch_id on subsequent addToQueue calls. */
-  item_ids?: number[];
+  cost_center_id?: number | null;
+  estimated_cost?: number | null;
 }
 
 export interface PrintQueueItemUpdate {
@@ -2036,6 +2035,8 @@ export interface PrintQueueItemUpdate {
   nozzle_offset_cali?: boolean;
   // Auto-print G-code injection
   gcode_injection?: boolean;
+  cost_center_id?: number | null;
+  estimated_cost?: number | null;
 }
 
 export interface PrintQueueBulkUpdate {
@@ -2055,6 +2056,7 @@ export interface PrintQueueBulkUpdate {
   nozzle_offset_cali?: boolean;
   // Auto-print G-code injection
   gcode_injection?: boolean;
+  cost_center_id?: number | null;
 }
 
 export interface PrintQueueBulkUpdateResponse {
@@ -2948,6 +2950,114 @@ export interface ExternalLinkUpdate {
   open_in_new_tab?: boolean;
 }
 
+// Finance types
+export interface CostCenterSummary {
+  id: number;
+  name: string;
+  is_private: boolean;
+  owner_user_id: number | null;
+  is_active: boolean;
+  total_balance: number;
+  total_budget: number | null;
+  monthly_budget: number | null;
+  budget_mode: 'none' | 'total' | 'monthly';
+  budget_limit: number | null;
+  budget_used: number | null;
+  budget_available: number | null;
+  can_print: boolean;
+}
+
+export interface CostCenterCreateRequest {
+  name: string;
+  total_budget?: number | null;
+  monthly_budget?: number | null;
+  is_active?: boolean;
+}
+
+export interface CostCenterBudgetUpdateRequest {
+  total_budget?: number | null;
+  monthly_budget?: number | null;
+}
+
+export interface CostCenterUpdateRequest {
+  name?: string;
+  is_active?: boolean;
+}
+
+export interface CostCenterMemberRequest {
+  user_id: number;
+  can_print?: boolean;
+}
+
+export interface CostCenterMemberResponse {
+  id: number;
+  cost_center_id: number;
+  user_id: number;
+  can_print: boolean;
+  created_at: string;
+}
+
+export interface CostCenterDetail extends CostCenterSummary {
+  members: CostCenterMemberResponse[];
+}
+
+export interface WalletBalance {
+  user_id: number;
+  balance: number;
+  currency: string;
+  updated_at: string | null;
+}
+
+export type WalletTransactionType = 'print_charge' | 'deposit' | 'withdraw' | 'manual_adjustment';
+
+export interface WalletTransaction {
+  id: number;
+  user_id: number;
+  cost_center_id: number | null;
+  transaction_type: WalletTransactionType;
+  amount: number;
+  balance_after: number | null;
+  description: string | null;
+  created_by_user_id: number | null;
+  print_run_id: string | null;
+  print_archive_id: number | null;
+  print_queue_id: number | null;
+  created_at: string;
+}
+
+export interface WalletTransactionListResponse {
+  items: WalletTransaction[];
+  total: number;
+  limit: number;
+  offset: number;
+}
+
+export interface WalletAdjustmentRequest {
+  amount: number;
+  description?: string;
+  cost_center_id?: number | null;
+}
+
+export interface WalletAdjustmentResponse {
+  transaction: WalletTransaction;
+  balance: WalletBalance;
+}
+
+export interface TransactionEditRequest {
+  user_id?: number | null;
+  cost_center_id?: number | null;
+  amount?: number | null;
+  description?: string | null;
+}
+
+export interface ManualPrintRequest {
+  user_id: number;
+  cost_center_id: number;
+  amount: number;
+  description?: string | null;
+  created_at?: string | null;
+}
+
 // Permission type - all available permissions
 export type Permission =
   | 'printers:read' | 'printers:create' | 'printers:update' | 'printers:delete' | 'printers:control' | 'printers:files' | 'printers:ams_rfid' | 'printers:clear_plate'
@@ -2974,6 +3084,7 @@ export type Permission =
   | 'discovery:scan'
   | 'firmware:read' | 'firmware:update'
   | 'ams_history:read'
+  | 'cost_centers:read_own' | 'cost_centers:read_all' | 'cost_centers:modify' | 'cost_centers:create'
   | 'stats:read' | 'stats:filter_by_user'
   | 'system:read'
   | 'settings:read' | 'settings:update' | 'settings:backup' | 'settings:restore'
@@ -4373,6 +4484,8 @@ export const api = {
       vibration_cali?: boolean;
       layer_inspect?: boolean;
       use_ams?: boolean;
+      cost_center_id?: number;
+      estimated_cost?: number;
       nozzle_offset_cali?: boolean;
     }
   ) =>
@@ -4784,16 +4897,6 @@ export const api = {
   getBatch: (id: number) => request<PrintBatch>(`/queue/batches/${id}`),
   cancelBatch: (id: number) =>
     request<{ message: string }>(`/queue/batches/${id}`, { method: 'DELETE' }),
-  createBatch: (data: PrintBatchCreate) =>
-    request<PrintBatch>('/queue/batches', {
-      method: 'POST',
-      body: JSON.stringify(data),
-    }),
-  ungroupBatch: (id: number) =>
-    request<{ ungrouped_count: number; message: string }>(
-      `/queue/batches/${id}/ungroup`,
-      { method: 'POST' },
-    ),
 
   // K-Profiles
   getKProfiles: (printerId: number, nozzleDiameter = '0.4') =>
@@ -4813,6 +4916,80 @@ export const api = {
       method: 'POST',
       body: JSON.stringify(profiles),
     }),
+  
+  // Finance
+  getMyBalance: () => request<WalletBalance>('/finance/me/balance'),
+  getMyTransactions: (limit = 50, offset = 0) =>
+    request<WalletTransactionListResponse>(`/finance/me/transactions?limit=${limit}&offset=${offset}`),
+  getAllTransactions: (limit = 50, offset = 0, userId?: number) => {
+    const params = new URLSearchParams();
+    params.set('limit', String(limit));
+    params.set('offset', String(offset));
+    if (userId !== undefined) params.set('user_id', String(userId));
+    return request<WalletTransactionListResponse>(`/finance/transactions?${params.toString()}`);
+  },
+  deleteTransaction: (transactionId: number) =>
+    request<{ status: string }>(`/finance/transactions/${transactionId}`, {
+      method: 'DELETE',
+    }),
+  editTransaction: (transactionId: number, data: TransactionEditRequest) =>
+    request<WalletTransaction>(`/finance/transactions/${transactionId}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    }),
+  createManualPrint: (data: ManualPrintRequest) =>
+    request<WalletTransaction>(`/finance/transactions/manual`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
+  getMyCostCenters: () => request<CostCenterSummary[]>('/finance/cost-centers/mine'),
+  listCostCenters: (includeInactive = false) =>
+    request<CostCenterSummary[]>(`/finance/cost-centers?include_inactive=${includeInactive ? 'true' : 'false'}`),
+  createCostCenter: (data: CostCenterCreateRequest) =>
+    request<CostCenterSummary>('/finance/cost-centers', {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
+  updateCostCenter: (costCenterId: number, data: CostCenterUpdateRequest) =>
+    request<CostCenterSummary>(`/finance/cost-centers/${costCenterId}`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    }),
+  updateCostCenterBudgets: (costCenterId: number, data: CostCenterBudgetUpdateRequest) =>
+    request<CostCenterSummary>(`/finance/cost-centers/${costCenterId}/budgets`, {
+      method: 'PATCH',
+      body: JSON.stringify(data),
+    }),
+  deleteCostCenter: (costCenterId: number) =>
+    request<{ status: string }>(`/finance/cost-centers/${costCenterId}`, {
+      method: 'DELETE',
+    }),
+  getCostCenter: (costCenterId: number) =>
+    request<CostCenterDetail>(`/finance/cost-centers/${costCenterId}`),
+  upsertCostCenterMember: (costCenterId: number, data: CostCenterMemberRequest) =>
+    request<CostCenterMemberResponse>(`/finance/cost-centers/${costCenterId}/members`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
+  removeCostCenterMember: (costCenterId: number, userId: number) =>
+    request<{ status: string }>(`/finance/cost-centers/${costCenterId}/members/${userId}`, {
+      method: 'DELETE',
+    }),
+  depositUserBalance: (userId: number, data: WalletAdjustmentRequest) =>
+    request<WalletAdjustmentResponse>(`/finance/users/${userId}/deposit`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
+  withdrawUserBalance: (userId: number, data: WalletAdjustmentRequest) =>
+    request<WalletAdjustmentResponse>(`/finance/users/${userId}/withdraw`, {
+      method: 'POST',
+      body: JSON.stringify(data),
+    }),
+  rebuildBalanceLedger: () =>
+    request<{ status: string }>(`/finance/rebuild-balance-ledger`, {
+      method: 'POST',
+    }),
+
 
   // K-Profile Notes (stored locally, not on printer)
   getKProfileNotes: (printerId: number) =>
@@ -6054,6 +6231,8 @@ export const api = {
       nozzle_offset_cali?: boolean;
       project_id?: number;
       cleanup_library_after_dispatch?: boolean;
+      cost_center_id?: number;
+      estimated_cost?: number;
     }
   ) =>
     request<BackgroundDispatchResponse>(

frontend/src/components/Layout.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect, useCallback, useRef, useMemo } from 'react';
 import { NavLink, Outlet, useNavigate, useLocation } from 'react-router-dom';
-import { Printer, Archive, ListOrdered, BarChart3, Cloud, Settings, Sun, Moon, Monitor, ChevronLeft, ChevronRight, Keyboard, Github, ArrowUpCircle, Wrench, FolderKanban, FolderOpen, X, Menu, Info, Plug, Bug, LogOut, Key, Loader2, Disc3, ShieldAlert, Globe, type LucideIcon } from 'lucide-react';
+import { Printer, Archive, ListOrdered, BarChart3, Cloud, Settings, Sun, Moon, Monitor, ChevronLeft, ChevronRight, Keyboard, Github, ArrowUpCircle, Wrench, FolderKanban, FolderOpen, X, Menu, Info, Plug, Bug, LogOut, Key, Loader2, Disc3, ShieldAlert, Globe, Wallet, type LucideIcon } from 'lucide-react';
 import { useTranslation } from 'react-i18next';
 import { useTheme } from '../contexts/ThemeContext';
 import { KeyboardShortcutsModal } from './KeyboardShortcutsModal';
@@ -43,6 +43,7 @@ export const defaultNavItems: NavItem[] = [
   { id: 'archives', to: '/archives', icon: Archive, labelKey: 'nav.archives' },
   { id: 'queue', to: '/queue', icon: ListOrdered, labelKey: 'nav.queue' },
   { id: 'projects', to: '/projects', icon: FolderKanban, labelKey: 'nav.projects' },
+  { id: 'finance', to: '/finance', icon: Wallet, labelKey: 'nav.finance' },
   { id: 'files', to: '/files', icon: FolderOpen, labelKey: 'nav.files' },
   { id: 'makerworld', to: '/makerworld', icon: Globe, labelKey: 'nav.makerworld' },
   { id: 'profiles', to: '/profiles', icon: Cloud, labelKey: 'nav.profiles' },
@@ -293,6 +294,7 @@ export function Layout() {
       maintenance: 'maintenance:read',
       projects: 'projects:read',
       inventory: 'inventory:read',
+      finance: 'cost_centers:read_own',
       files: ['library:read', 'library:read_own', 'library:read_all'],
       makerworld: 'makerworld:view',
       settings: 'settings:read',

frontend/src/components/PrintModal/CostCenterSelect.tsx

@@ -0,0 +1,38 @@
+import { useTranslation } from 'react-i18next';
+import type { CostCenterSummary } from '../../api/client';
+
+interface CostCenterSelectProps {
+  costCenters: CostCenterSummary[];
+  selectedCostCenterId: number | null;
+  onChange: (costCenterId: number | null) => void;
+}
+
+export function CostCenterSelect({
+  costCenters,
+  selectedCostCenterId,
+  onChange,
+}: CostCenterSelectProps) {
+  const { t } = useTranslation();
+
+  if (costCenters.length === 0) return null;
+
+  return (
+    <div className="space-y-1">
+      <label htmlFor="printCostCenter" className="text-sm text-bambu-gray">
+        {t('printModal.costCenter', 'Cost center')}
+      </label>
+      <select
+        id="printCostCenter"
+        value={selectedCostCenterId ?? ''}
+        onChange={(e) => onChange(e.target.value ? Number(e.target.value) : null)}
+        className="w-full px-3 py-2 text-sm bg-bambu-dark border border-bambu-dark-tertiary rounded text-white focus:outline-none focus:ring-1 focus:ring-bambu-green"
+      >
+        {costCenters.map((center) => (
+          <option key={center.id} value={center.id}>
+            {center.name}{center.is_private ? ` (${t('printModal.personalDefault', 'Personal')})` : ''}
+          </option>
+        ))}
+      </select>
+    </div>
+  );
+}

frontend/src/components/PrintModal/FilamentMapping.tsx

@@ -1,4 +1,4 @@
-import { useMemo, useState } from 'react';
+import { useEffect, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
 import { useQuery, useQueryClient } from '@tanstack/react-query';
 import { Circle, Check, AlertTriangle, RefreshCw, ChevronDown, ChevronUp, Palette } from 'lucide-react';
@@ -18,6 +18,9 @@ export function FilamentMapping({
   filamentReqs,
   manualMappings,
   onManualMappingChange,
+  onEstimatedCostChange,
+  budgetAvailable,
+  quantity = 1,
   currencySymbol,
   defaultCostPerKg,
   defaultExpanded = false,
@@ -118,10 +121,16 @@ export function FilamentMapping({
     return total;
   }, [filamentComparison, trayCostMap, defaultCostPerKg]);
 
+  useEffect(() => {
+    onEstimatedCostChange?.(totalCost > 0 ? totalCost : null);
+  }, [onEstimatedCostChange, totalCost]);
+
   const hasAnyCost = useMemo(
     () => Array.from(trayCostMap.values()).some((v) => v != null && v > 0),
     [trayCostMap]
   );
+  const budgetCheckCost = totalCost * Math.max(1, quantity);
+  const isBudgetInsufficient = budgetAvailable != null && budgetCheckCost > budgetAvailable;
   const hasFilamentReqs = filamentReqs?.filaments && filamentReqs.filaments.length > 0;
   const isDualNozzle = filamentReqs?.filaments?.some((f) => f.nozzle_id != null) ?? false;
 
@@ -344,7 +353,19 @@ export function FilamentMapping({
             <span className="text-white">
               {totalCost > 0 || hasAnyCost ? `${currencySymbol}${totalCost.toFixed(2)}` : 'N/A'}
             </span>
+            {quantity > 1 && totalCost > 0 && (
+              <span className="ml-2">
+                {t('printModal.totalCostForQuantity', 'total: {{cost}}', {
+                  cost: `${currencySymbol}${budgetCheckCost.toFixed(2)}`,
+                })}
+              </span>
+            )}
           </div>
+          {isBudgetInsufficient && (
+            <p className="text-xs text-red-400 mt-2">
+              {t('printModal.insufficientBudget', 'Insufficient budget for this cost center.')}
+            </p>
+          )}
           {hasTypeMismatch && (
             <p className="text-xs text-orange-400 mt-2">Required filament type not found in printer.</p>
           )}

frontend/src/components/PrintModal/index.tsx

@@ -2,7 +2,7 @@ import { useMutation, useQueries, useQuery, useQueryClient } from '@tanstack/rea
 import { AlertCircle, AlertTriangle, Calendar, Code, Layers, Loader2, Pencil, Printer, X } from 'lucide-react';
 import { useEffect, useMemo, useRef, useState } from 'react';
 import { useTranslation } from 'react-i18next';
-import type { PrintQueueItemCreate, PrintQueueItemUpdate, SpoolAssignment } from '../../api/client';
+import type { PrintQueueItemCreate, PrintQueueItemUpdate, SpoolAssignment, CostCenterSummary } from '../../api/client';
 import { api } from '../../api/client';
 import { useAuth } from '../../contexts/AuthContext';
 import { Card, CardContent } from '../Card';
@@ -22,6 +22,7 @@ import { PlateSelector } from './PlateSelector';
 import { PrinterSelector } from './PrinterSelector';
 import { PrintOptionsPanel } from './PrintOptions';
 import { ScheduleOptionsPanel } from './ScheduleOptions';
+import { CostCenterSelect } from './CostCenterSelect';
 import type {
   AssignmentMode,
   PrintModalProps,
@@ -55,7 +56,7 @@ export function PrintModal({
   const { t } = useTranslation();
   const queryClient = useQueryClient();
   const { showToast } = useToast();
-  const { hasPermission } = useAuth();
+  const { hasPermission, user } = useAuth();
 
   // Determine if we're printing a library file
   const isLibraryFile = !!libraryFileId && !archiveId;
@@ -179,6 +180,15 @@ export function PrintModal({
     return null;
   });
 
+  // Cost center selection (defaults to queue item's value in edit mode)
+  const [selectedCostCenterId, setSelectedCostCenterId] = useState<number | null>(() => {
+    if (mode === 'edit-queue-item' && queueItem?.cost_center_id != null) {
+      return queueItem.cost_center_id;
+    }
+    return null;
+  });
+  const [estimatedCost, setEstimatedCost] = useState<number | null>(queueItem?.estimated_cost ?? null);
+
   // Filament overrides for model-based assignment: slot_id -> {type, color}
   const [filamentOverrides, setFilamentOverrides] = useState<Record<number, { type: string; color: string }>>(() => {
     if (mode === 'edit-queue-item' && queueItem?.filament_overrides) {
@@ -257,12 +267,37 @@ export function PrintModal({
 
   const currencySymbol = getCurrencySymbol(settings?.currency || 'USD');
   const defaultCostPerKg = settings?.default_filament_cost ?? 0;
+  const billingEnabled = settings?.billing_enabled === true;
 
   const { data: printers, isLoading: loadingPrinters } = useQuery({
     queryKey: ['printers'],
     queryFn: api.getPrinters,
   });
 
+  const { data: myCostCenters } = useQuery({
+    queryKey: ['finance', 'cost-centers', 'mine'],
+    queryFn: api.getMyCostCenters,
+    enabled: !!user && billingEnabled,
+  });
+
+  const printableCostCenters = useMemo(
+    () => (myCostCenters || []).filter((center: CostCenterSummary) => center.can_print && center.is_active),
+    [myCostCenters]
+  );
+  const selectedCostCenter = useMemo(
+    () => printableCostCenters.find((center) => center.id === selectedCostCenterId) ?? null,
+    [printableCostCenters, selectedCostCenterId]
+  );
+
+  // Select default cost center once loaded (prefer private/personal)
+  useEffect(() => {
+    if (printableCostCenters.length === 0) return;
+    if (selectedCostCenterId != null && printableCostCenters.some((c) => c.id === selectedCostCenterId)) return;
+
+    const preferredPrivate = printableCostCenters.find((c) => c.is_private);
+    setSelectedCostCenterId(preferredPrivate ? preferredPrivate.id : printableCostCenters[0].id);
+  }, [printableCostCenters, selectedCostCenterId]);
+
   const { data: spoolAssignments } = useQuery({
     queryKey: ['spool-assignments'],
     queryFn: () => api.getAssignments(),
@@ -733,6 +768,8 @@ export function PrintModal({
         : undefined,
       ...printOptions,
       project_id: projectId ?? undefined,
+      cost_center_id: billingEnabled ? selectedCostCenterId : undefined,
+      estimated_cost: billingEnabled && selectedCostCenterId != null ? estimatedCost : undefined,
       batch_id: autoBatchId ?? undefined,
     });
 
@@ -768,6 +805,8 @@ export function PrintModal({
                 ? new Date(scheduleOptions.scheduledTime).toISOString()
                 : null,
               ...printOptions,
+              cost_center_id: billingEnabled ? selectedCostCenterId : undefined,
+              estimated_cost: billingEnabled && selectedCostCenterId != null ? estimatedCost : undefined,
             };
             await updateQueueMutation.mutateAsync(updateData);
           } else {
@@ -826,7 +865,9 @@ export function PrintModal({
                     ...printOptions,
                     project_id: projectId,
                     cleanup_library_after_dispatch: cleanupLibraryAfterDispatch,
-                  });
+                    cost_center_id: billingEnabled ? selectedCostCenterId ?? undefined : undefined,
+                    estimated_cost: billingEnabled && selectedCostCenterId != null ? estimatedCost ?? undefined : undefined,
+                });
                 } else {
                   // project_id is intentionally omitted here: reprintArchive targets an existing
                   // archive that already carries its own project association from the original print.
@@ -835,7 +876,9 @@ export function PrintModal({
                     plate_name: selectedPlateName,
                     ams_mapping: printerMapping,
                     ...printOptions,
-                  });
+                    cost_center_id: billingEnabled ? selectedCostCenterId ?? undefined : undefined,
+                    estimated_cost: billingEnabled && selectedCostCenterId != null ? estimatedCost ?? undefined : undefined,
+                });
                 }
                 // Queue remaining copies if quantity > 1
                 if (effectiveQuantity > 1) {
@@ -861,6 +904,8 @@ export function PrintModal({
                   ? new Date(scheduleOptions.scheduledTime).toISOString()
                   : null,
                 ...printOptions,
+                cost_center_id: billingEnabled ? selectedCostCenterId : undefined,
+                estimated_cost: billingEnabled && selectedCostCenterId != null ? estimatedCost : undefined,
               };
               await updateQueueMutation.mutateAsync(updateData);
             } else {
@@ -1020,6 +1065,12 @@ export function PrintModal({
     isLibraryFile || (isMultiPlate ? selectedPlate !== null : true)
   );
 
+  useEffect(() => {
+    if (!showFilamentMapping || archiveDataMissing || selectedPrinters.length !== 1) {
+      setEstimatedCost(null);
+    }
+  }, [archiveDataMissing, selectedPrinters.length, showFilamentMapping]);
+
   // Dual-nozzle gate for the Nozzle Offset Calibration toggle (#1682).
   // Mirrors backend `DUAL_NOZZLE_MODELS` so model-based assignment can show
   // the toggle without a specific printer selected. For printer-mode we rely
@@ -1199,6 +1250,9 @@ export function PrintModal({
                 filamentReqs={effectiveFilamentReqs}
                 manualMappings={manualMappings}
                 onManualMappingChange={setManualMappings}
+                onEstimatedCostChange={setEstimatedCost}
+                budgetAvailable={billingEnabled ? selectedCostCenter?.budget_available ?? null : null}
+                quantity={effectiveQuantity}
                 defaultExpanded={!!initialSelectedPrinterIds?.length || (settings?.per_printer_mapping_expanded ?? false)}
                 currencySymbol={currencySymbol}
                 defaultCostPerKg={defaultCostPerKg}
@@ -1217,6 +1271,12 @@ export function PrintModal({
                 defaultExpanded={!!initialSelectedPrinterIds?.length}
                 showDualNozzleOptions={showDualNozzleOptions}
               />
+            {billingEnabled && printableCostCenters.length > 0 && (
+              <CostCenterSelect
+                costCenters={printableCostCenters}
+                selectedCostCenterId={selectedCostCenterId}
+                onChange={setSelectedCostCenterId}
+              />
             )}
 
             {/* Quantity — create multiple copies (batch). Hidden for multi-printer selection. */}
@@ -1311,6 +1371,13 @@ export function PrintModal({
               </div>
             )}
 
+            {/* Print options */}
+            {(mode === 'reprint' || effectivePrinterCount > 0 || (assignmentMode === 'model' && targetModel)) && (
+              <div className="pt-3">
+                <PrintOptionsPanel options={printOptions} onChange={setPrintOptions} defaultExpanded={!!initialSelectedPrinterIds?.length} />
+              </div>
+            )}
+
             {/* Error message */}
             {updateQueueMutation.isError && (
               <div className="mb-4 p-3 bg-red-500/20 border border-red-500/50 rounded-lg text-sm text-red-400">
@@ -1319,7 +1386,7 @@ export function PrintModal({
             )}
 
             {/* Actions */}
-            <div className={`flex gap-3 ${mode === 'reprint' ? '' : 'pt-2'}`}>
+            <div className="flex gap-3 pt-4 mt-2 border-t border-bambu-dark-tertiary">
               <Button type="button" variant="secondary" onClick={onClose} className="flex-1" disabled={isSubmitting}>
                 Cancel
               </Button>

frontend/src/components/PrintModal/types.ts

@@ -199,6 +199,9 @@ export interface FilamentMappingProps {
   filamentReqs: FilamentReqsData | undefined;
   manualMappings: Record<number, number>;
   onManualMappingChange: (mappings: Record<number, number>) => void;
+  onEstimatedCostChange?: (estimatedCost: number | null) => void;
+  budgetAvailable?: number | null;
+  quantity?: number;
   currencySymbol: string;
   defaultCostPerKg: number;
   /** Per-slot force-color-match flags. The scheduler honors this flag in both

frontend/src/pages/SettingsPage.tsx

@@ -182,6 +182,8 @@ export function SettingsPage() {
   const [templateFilter, setTemplateFilter] = useState('');
   const [settingsSearch, setSettingsSearch] = useState('');
   const [showLogViewer, setShowLogViewer] = useState(false);
+  const [showRebuildConfirm, setShowRebuildConfirm] = useState(false);
+  const [isRebuildLoading, setIsRebuildLoading] = useState(false);
   const [defaultView, setDefaultViewState] = useState<string>(getDefaultView());
 
   // Initialize tab from URL params (handle legacy ?tab=email → users tab + email sub-tab)
@@ -992,6 +994,11 @@ export function SettingsPage() {
       (settings.chamber_temp_presets ?? '') !== (localSettings.chamber_temp_presets ?? '') ||
       (settings.fan_speed_presets ?? '') !== (localSettings.fan_speed_presets ?? '') ||
       (settings.session_max_hours ?? 24) !== (localSettings.session_max_hours ?? 24);
+      (settings.require_plate_clear ?? false) !== (localSettings.require_plate_clear ?? false) ||
+      (settings.billing_enabled ?? false) !== (localSettings.billing_enabled ?? false) ||
+      (settings.printer_kill_switch_enabled ?? false) !== (localSettings.printer_kill_switch_enabled ?? false) ||
+      (settings.finance_budget_reset_day ?? 1) !== (localSettings.finance_budget_reset_day ?? 1) ||
+      (settings.finance_budget_reset_timezone ?? 'UTC') !== (localSettings.finance_budget_reset_timezone ?? 'UTC');
 
     if (!hasChanges) {
       return;
@@ -1084,6 +1091,10 @@ export function SettingsPage() {
         chamber_temp_presets: localSettings.chamber_temp_presets,
         fan_speed_presets: localSettings.fan_speed_presets,
         session_max_hours: localSettings.session_max_hours,
+        billing_enabled: localSettings.billing_enabled,
+        printer_kill_switch_enabled: localSettings.printer_kill_switch_enabled,
+        finance_budget_reset_day: localSettings.finance_budget_reset_day,
+        finance_budget_reset_timezone: localSettings.finance_budget_reset_timezone,
       };
       updateMutation.mutate(settingsToSave);
     }, 500);
@@ -2129,6 +2140,151 @@ export function SettingsPage() {
                     : t('settings.energyModeTotalDescription')}
                 </p>
               </div>
+              <div>
+                <div className="flex items-center justify-between">
+                  <div>
+                    <p className="text-white">{t('settings.billingEnabled')}</p>
+                    <p className="text-xs text-bambu-gray">{t('settings.billingEnabledDescription')}</p>
+                  </div>
+                  <label className="relative inline-flex items-center cursor-pointer">
+                    <input
+                      type="checkbox"
+                      checked={localSettings.billing_enabled ?? false}
+                      onChange={(e) => updateSetting('billing_enabled', e.target.checked)}
+                      className="peer sr-only"
+                    />
+                    <div className="w-11 h-6 bg-bambu-dark-tertiary rounded-full peer-checked:bg-bambu-green peer-checked:after:translate-x-5 after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:border after:rounded-full after:h-5 after:w-5 after:transition-all" />
+                  </label>
+                </div>
+                {localSettings.billing_enabled && (
+                  <div className="mt-4 flex items-center justify-between gap-4 rounded-lg border border-bambu-dark-tertiary bg-bambu-dark px-4 py-3">
+                    <div className="flex-1">
+                      <p className="text-white">
+                        {t('settings.printerKillSwitch', 'Unauthorized print kill switch')}
+                      </p>
+                      <p className="text-xs text-bambu-gray mt-1">
+                        {t(
+                          'settings.printerKillSwitchDescription',
+                          'Immediately stop prints that start without authorization.'
+                        )}
+                      </p>
+                    </div>
+                    <label className="relative inline-flex items-center cursor-pointer">
+                      <input
+                        type="checkbox"
+                        checked={localSettings.printer_kill_switch_enabled ?? false}
+                        onChange={(e) => updateSetting('printer_kill_switch_enabled', e.target.checked)}
+                        className="peer sr-only"
+                      />
+                      <div className="w-11 h-6 bg-bambu-dark-tertiary rounded-full peer-checked:bg-bambu-green peer-checked:after:translate-x-5 after:content-[''] after:absolute after:top-[2px] after:left-[2px] after:bg-white after:border after:rounded-full after:h-5 after:w-5 after:transition-all" />
+                    </label>
+                  </div>
+                )}
+                {localSettings.billing_enabled && (
+                  <div className="mt-4 rounded-lg border border-bambu-dark-tertiary bg-bambu-dark p-4">
+                    <div className="mb-3">
+                      <h4 className="text-base font-medium text-white flex items-center gap-2">
+                        <Calendar className="w-4 h-4 text-bambu-green" />
+                        {t('settings.financeBudgetReset', 'Finance Monthly Budget Reset')}
+                      </h4>
+                    </div>
+                    <div className="flex gap-4">
+                      <div className="flex-1">
+                        <label className="block text-xs text-bambu-gray mb-1">
+                          {t('settings.financeBudgetResetDay', 'Reset Day')}
+                        </label>
+                        <input
+                          type="number"
+                          min={1}
+                          max={31}
+                          value={localSettings.finance_budget_reset_day ?? 1}
+                          onChange={(e) =>
+                            updateSetting(
+                              'finance_budget_reset_day',
+                              Math.max(1, Math.min(31, parseInt(e.target.value, 10) || 1))
+                            )
+                          }
+                          className="w-full px-3 py-2 bg-bambu-dark border border-bambu-dark-tertiary rounded-lg text-white text-sm focus:outline-none focus:border-bambu-green"
+                        />
+                        <p className="text-xs text-bambu-gray mt-1">
+                          {t('settings.financeBudgetResetDayHelp', 'For short months, reset uses the last day of the month.')}
+                        </p>
+                      </div>
+                      <div className="flex-1">
+                        <label className="block text-xs text-bambu-gray mb-1">
+                          {t('settings.financeBudgetResetTimezone', 'Reset timezone')}
+                        </label>
+                        <select
+                          value={localSettings.finance_budget_reset_timezone ?? 'UTC'}
+                          onChange={(e) => updateSetting('finance_budget_reset_timezone', e.target.value)}
+                          className="w-full px-3 py-2 bg-bambu-dark border border-bambu-dark-tertiary rounded-lg text-white text-sm focus:outline-none focus:border-bambu-green"
+                        >
+                          <option value="UTC">UTC</option>
+                          <option value="Europe/Berlin">Europe/Berlin</option>
+                          <option value="Europe/Vienna">Europe/Vienna</option>
+                          <option value="Europe/Zurich">Europe/Zurich</option>
+                          <option value="America/New_York">America/New_York</option>
+                          <option value="America/Chicago">America/Chicago</option>
+                          <option value="America/Denver">America/Denver</option>
+                          <option value="America/Los_Angeles">America/Los_Angeles</option>
+                          <option value="Asia/Tokyo">Asia/Tokyo</option>
+                          <option value="Asia/Singapore">Asia/Singapore</option>
+                          <option value="Australia/Sydney">Australia/Sydney</option>
+                        </select>
+                        <p className="text-xs text-bambu-gray mt-1">
+                          {t('settings.financeBudgetResetTimezoneHelp', 'Budget window start is calculated in this timezone.')}
+                        </p>
+                      </div>
+                    </div>
+                  </div>
+                )}
+                {localSettings.billing_enabled && isAdmin && (
+                  <div className="mt-3">
+                    <Button
+                      variant="secondary"
+                      onClick={() => setShowRebuildConfirm(true)}
+                      disabled={isRebuildLoading}
+                    >
+                      {isRebuildLoading ? (
+                        <>
+                          <Loader2 className="w-4 h-4 mr-2 animate-spin" />
+                          {t('settings.rebuildLedgerInProgress', 'Starting...')}
+                        </>
+                      ) : (
+                        t('settings.rebuildLedger', 'Rebuild wallet ledger')
+                      )}
+                    </Button>
+
+                    {showRebuildConfirm && (
+                      <ConfirmModal
+                        title={t('settings.rebuildLedgerConfirmTitle', 'Rebuild wallet ledger?')}
+                        message={t(
+                          'settings.rebuildLedgerConfirmMessage',
+                          'This will rebuild the wallet ledger to repair historical balance values. Run this only if you know what you are doing.'
+                        )}
+                        confirmText={t('common.run', 'Run')}
+                        cancelText={t('common.cancel', 'Cancel')}
+                        isLoading={isRebuildLoading}
+                        loadingText={t('common.running', 'Running')}
+                        variant="warning"
+                        onCancel={() => setShowRebuildConfirm(false)}
+                        onConfirm={async () => {
+                          setIsRebuildLoading(true);
+                          try {
+                            await api.rebuildBalanceLedger();
+                            showToast(t('settings.rebuildLedgerStarted', 'Ledger rebuild started'), 'success');
+                            setShowRebuildConfirm(false);
+                          } catch (err) {
+                            showToast((err as Error).message || 'Failed to start ledger rebuild', 'error');
+                          } finally {
+                            setIsRebuildLoading(false);
+                          }
+                        }}
+                      />
+                    )}
+                  </div>
+                )}
+              </div>
             </CardContent>
           </Card>