feat(notifications): dedicate AI Failure Detection notification event (#1794)

Split Obico failure-detection dispatch out of the multiplexed
  on_printer_error event onto its own on_ai_failure_detection event so
  users can subscribe to AI alerts without also enabling HMS hardware-
  error pages, and so the discoverable label "AI Failure Detection" is
  what subscribes them rather than the unrelated "Printer Error" toggle.

  New column on notification_providers (default False, branched
  SQLite/Postgres migration), new notification_service.on_ai_failure_detection
  method, new ai_failure_detection template, obico_actions._notify swap.
  Frontend gets a summary badge, a toggle row with description, and ntfy
  priority surfacing. 14 new tests pin the routing + the regression guard
  ("Printer Error" alone must NOT receive AI notifications now). 11 locales
  covered.

  Existing providers keep working: HMS hardware errors continue to ride
  on_printer_error unchanged; users who want spaghetti alerts opt in via
  the new toggle.

frontend/src/__tests__/components/AddNotificationModal.test.tsx

@@ -40,6 +40,7 @@ function buildProvider(overrides: Partial<NotificationProvider> = {}): Notificat
     on_print_missing_spool_assignment: false,
     on_printer_offline: false,
     on_printer_error: false,
+    on_ai_failure_detection: false,
     on_filament_low: false,
     on_maintenance_due: false,
     on_ams_humidity_high: false,
@@ -336,3 +337,52 @@ describe('AddNotificationModal — stock alert toggles', () => {
     void user; // referenced to avoid unused-var lint warning
   });
 });
+
+describe('AddNotificationModal — AI Failure Detection toggle (#1794)', () => {
+  it('renders the toggle in the Printer Status section', async () => {
+    render(<AddNotificationModal provider={buildProvider()} onClose={() => undefined} />);
+
+    expect(await screen.findByText('AI Failure Detection')).toBeInTheDocument();
+  });
+
+  it('persists on_ai_failure_detection on save (and does NOT touch on_printer_error)', async () => {
+    let captured: Record<string, unknown> | null = null;
+    server.use(
+      http.patch('*/api/v1/notifications/1', async ({ request }) => {
+        captured = (await request.json()) as Record<string, unknown>;
+        return HttpResponse.json({ id: 1 });
+      }),
+    );
+
+    const onClose = vi.fn();
+    const user = userEvent.setup();
+    render(<AddNotificationModal provider={buildProvider()} onClose={onClose} />);
+
+    const label = await screen.findByText('AI Failure Detection');
+    const row = label.closest('div.flex')!;
+    const toggle = within(row).getByRole('switch');
+    await user.click(toggle);
+
+    await user.click(screen.getByRole('button', { name: /^save$/i }));
+    await waitFor(() => expect(onClose).toHaveBeenCalled());
+
+    expect(captured).not.toBeNull();
+    expect(captured!.on_ai_failure_detection).toBe(true);
+    // Critical regression guard: don't accidentally flip the legacy multiplexed field.
+    expect(captured!.on_printer_error).toBe(false);
+  });
+
+  it('AI Failure Detection appears in ntfy priority section when enabled', async () => {
+    render(
+      <AddNotificationModal
+        provider={buildProvider({ on_ai_failure_detection: true })}
+        onClose={() => undefined}
+      />,
+    );
+
+    const priorityHeader = await screen.findByText(/ntfy priority/i);
+    const priorityRoot = priorityHeader.closest('div')!;
+
+    expect(within(priorityRoot).getByText('AI Failure Detection')).toBeInTheDocument();
+  });
+});

frontend/src/__tests__/components/NotificationProviderCard.test.tsx

@@ -57,6 +57,7 @@ const createMockProvider = (
   on_print_progress: false,
   on_printer_offline: false,
   on_printer_error: false,
+  on_ai_failure_detection: false,
   on_filament_low: false,
   on_maintenance_due: false,
   on_ams_humidity_high: false,

frontend/src/__tests__/components/NotificationProviderCardAiFailureDetection.test.tsx

@@ -0,0 +1,128 @@
+/**
+ * Tests for the AI Failure Detection toggle on NotificationProviderCard (#1794).
+ *
+ * Before #1794, Obico failure detection rode the multiplexed
+ * on_printer_error toggle so users couldn't subscribe to one without the
+ * other. These tests pin the standalone toggle:
+ *  - Summary badge renders when enabled.
+ *  - The toggle row appears in the expanded settings panel.
+ *  - Flipping the toggle PATCHes the correct field.
+ */
+
+import { describe, it, expect, afterEach, vi } from 'vitest';
+import { screen, waitFor, within } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import { http, HttpResponse } from 'msw';
+import { render } from '../utils';
+import { server } from '../mocks/server';
+import { NotificationProviderCard } from '../../components/NotificationProviderCard';
+import type { NotificationProvider } from '../../api/client';
+
+afterEach(() => {
+  server.resetHandlers();
+  vi.restoreAllMocks();
+});
+
+function buildProvider(overrides: Partial<NotificationProvider> = {}): NotificationProvider {
+  return {
+    id: 1,
+    name: 'Test Provider',
+    provider_type: 'ntfy',
+    enabled: true,
+    config: { server: 'https://ntfy.sh', topic: 'bambuddy' },
+    on_print_start: false,
+    on_print_complete: false,
+    on_print_failed: false,
+    on_print_stopped: false,
+    on_print_progress: false,
+    on_print_missing_spool_assignment: false,
+    on_printer_offline: false,
+    on_printer_error: false,
+    on_ai_failure_detection: false,
+    on_filament_low: false,
+    on_maintenance_due: false,
+    on_ams_humidity_high: false,
+    on_ams_temperature_high: false,
+    on_ams_ht_humidity_high: false,
+    on_ams_ht_temperature_high: false,
+    on_plate_not_empty: false,
+    on_bed_cooled: false,
+    on_first_layer_complete: false,
+    on_queue_job_added: false,
+    on_queue_job_assigned: false,
+    on_queue_job_started: false,
+    on_queue_job_waiting: false,
+    on_queue_job_skipped: false,
+    on_queue_job_failed: false,
+    on_queue_completed: false,
+    on_stock_reorder_alert: false,
+    on_stock_break_alert: false,
+    quiet_hours_enabled: false,
+    quiet_hours_start: null,
+    quiet_hours_end: null,
+    daily_digest_enabled: false,
+    daily_digest_time: null,
+    printer_id: null,
+    last_success: null,
+    last_error: null,
+    last_error_at: null,
+    created_at: '2026-06-22T00:00:00Z',
+    updated_at: '2026-06-22T00:00:00Z',
+    ...overrides,
+  };
+}
+
+describe('NotificationProviderCard — AI Failure Detection badge', () => {
+  it('renders the badge when on_ai_failure_detection is true', async () => {
+    render(
+      <NotificationProviderCard
+        provider={buildProvider({ on_ai_failure_detection: true })}
+        onEdit={vi.fn()}
+      />,
+    );
+    expect(await screen.findByText('AI Failure Detection')).toBeInTheDocument();
+  });
+
+  it('omits the badge when on_ai_failure_detection is false', async () => {
+    render(<NotificationProviderCard provider={buildProvider()} onEdit={vi.fn()} />);
+    await screen.findByText('Test Provider');
+    expect(screen.queryByText('AI Failure Detection')).not.toBeInTheDocument();
+  });
+});
+
+describe('NotificationProviderCard — AI Failure Detection toggle', () => {
+  it('renders the toggle in the expanded settings panel', async () => {
+    const user = userEvent.setup();
+    render(<NotificationProviderCard provider={buildProvider()} onEdit={vi.fn()} />);
+
+    await user.click(await screen.findByText(/event settings/i));
+
+    expect(await screen.findByText('AI Failure Detection')).toBeInTheDocument();
+  });
+
+  it('PATCHes on_ai_failure_detection (NOT on_printer_error) when toggled on — #1794 regression guard', async () => {
+    let captured: Record<string, unknown> | null = null;
+    server.use(
+      http.patch('*/api/v1/notifications/1', async ({ request }) => {
+        captured = (await request.json()) as Record<string, unknown>;
+        return HttpResponse.json(buildProvider({ on_ai_failure_detection: true }));
+      }),
+    );
+
+    const user = userEvent.setup();
+    render(<NotificationProviderCard provider={buildProvider()} onEdit={vi.fn()} />);
+
+    await user.click(await screen.findByText(/event settings/i));
+
+    // The toggle label "AI Failure Detection" is unique to this row.
+    const label = await screen.findByText('AI Failure Detection');
+    const row = label.closest('div.flex')!;
+    const toggle = within(row).getByRole('switch');
+    await user.click(toggle);
+
+    await waitFor(() => expect(captured).not.toBeNull());
+    expect(captured).toMatchObject({ on_ai_failure_detection: true });
+    // Critical: must NOT also flip the legacy multiplexed field.
+    expect(captured).not.toHaveProperty('on_printer_error');
+  });
+});

frontend/src/__tests__/components/NotificationProviderCardStockAlerts.test.tsx

@@ -37,6 +37,7 @@ function buildProvider(overrides: Partial<NotificationProvider> = {}): Notificat
     on_print_missing_spool_assignment: false,
     on_printer_offline: false,
     on_printer_error: false,
+    on_ai_failure_detection: false,
     on_filament_low: false,
     on_maintenance_due: false,
     on_ams_humidity_high: false,