Add Print Queue UI and slicer post-processing script

- Create Print Queue page showing pending/completed/cancelled jobs
- Add needs_weighing filter to spool API for flagged spools
- Add IPrintJob interface and needs_weighing to ISpool model
- Add slicer_post_process.py for Elegoo/Orca Slicer integration
- Add translations for print queue feature
- Bump version to 0.23C.3

The workflow:
1. Slicer post-processing script creates pending print job
2. After print, user confirms (deducts filament) or cancels (flags for weighing)
3. Spools needing weigh-in are shown in Print Queue UI

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CLAUDE.md

@@ -136,12 +136,12 @@ This is a fork with UX improvements. Issues are tracked on the Gitea instance ab
 | 8 | (see Gitea #8) | ✅ DONE |
 | 9 | Hierarchical Locations (Room/Bin) | Open |
 | 10 | Database Import/Export | ✅ DONE |
-| 11 | Orca Slicer / Elegoo Slicer Integration | Open |
-| - | Theme Colors | ✅ DONE |
-| - | Clickable Dashboard Cards | ✅ DONE |
-| - | QR Code Size Setting | ✅ DONE |
-| - | Parse Temps from Comments | ✅ DONE |
-| - | Prev/Next Navigation on Edit Pages | ✅ DONE |
+| 11 | Theme Colors | ✅ DONE |
+| 12 | Clickable Dashboard Cards | ✅ DONE |
+| 13 | QR Code Size Setting | ✅ DONE |
+| 14 | Parse Temps from Comments | ✅ DONE |
+| 15 | Print Job Tracking / Slicer Integration | ✅ DONE |
+| 16 | Prev/Next Navigation on Edit Pages | ✅ DONE |
 
 ### Issue #1 Complete - Inline Creation Modals
 
@@ -314,6 +314,38 @@ Added explicit QR code size control:
 - `client/src/pages/printing/printing.tsx` - Added `qrCodeSize` to interface
 - `client/src/pages/printing/qrCodePrintingDialog.tsx` - Slider for size in mm (0=auto)
 
+### Issue #15 Complete - Print Job Tracking / Slicer Integration
+
+Track pending print jobs from slicer and manage filament deduction after prints complete.
+
+**Workflow:**
+1. Slicer post-processing script parses G-code for filament usage
+2. Script creates pending print job in Spoolman via API
+3. After print completes, user visits Print Queue UI
+4. Complete: Deducts filament from spool, records adjustment history
+5. Cancel: Flags spool for manual weigh-in (no automatic deduction)
+
+**Backend:**
+- `spoolman/database/models.py` - `PrintJob` model, `needs_weighing` field on Spool
+- `spoolman/database/print_job.py` - CRUD operations for print jobs
+- `spoolman/api/v1/print_job.py` - REST API endpoints
+  - `POST /print-job` - Create pending job
+  - `POST /print-job/{id}/complete` - Complete job, deduct filament
+  - `POST /print-job/{id}/cancel` - Cancel job, flag spool for weighing
+  - `GET /print-job` - List jobs with status filter
+- `migrations/versions/2025_01_15_0400-c3d4e5f6g7h8_add_print_jobs.py`
+
+**Frontend:**
+- `client/src/pages/print-queue/index.tsx` - Print Queue UI page
+- `client/src/pages/spools/model.tsx` - `IPrintJob` interface, `needs_weighing` on ISpool
+
+**Slicer Script:**
+- `scripts/slicer_post_process.py` - Elegoo/Orca Slicer post-processing script
+- Parses G-code comments for filament usage (weight in grams)
+- Creates pending print job via API
+- Configure via env vars: `SPOOLMAN_URL`, `SPOOLMAN_SPOOL_ID`
+- Or config file: `~/.config/spoolman/slicer.conf`
+
 ---
 
 ## Deployment