Brings the Spoolman writer up to parity with the internal-inventory
side, which has had this fallback since #1119. When a Bambu print
starts without a retrievable .gcode.3mf on the printer (typically an
unsaved BambuStudio project, subtask_name='Untitled'), Spoolman no
longer silently skips the print's filament consumption.
- ActivePrintSpoolman.filament_usage now nullable; new tray_remain_start
column captures per-slot {remain, tray_uuid} at print start.
- store_print_data: always snapshots remain, even when 3MF is present
(mirrors usage_tracker.on_print_start), so partial-3MF prints can also
fall back per-slot.
- report_usage: 3MF path stays primary; new _report_remain_delta_for_slots
handles slots the 3MF didn't cover via delta * Filament.weight / 100,
resolving the spool via the existing slot-assignment table.
- _report_partial_usage: same fallback for aborted no-3MF prints.
#1119 invariant preserved: per-slot, per-print, gated on a valid
start/current remain AND a resolvable Spoolman spool. Uses curated
Filament.weight (not MQTT's unreliable tray_weight) — same trick the
internal-inventory side uses.
Mid-print spool swap detected via tray_uuid mismatch → slot skipped.
Double-charge prevented via handled_global_tray_ids dedup.
maziggy
e09a33be16