feat(greenfield): rebuild SlabUploader M1-M3 on clean foundation, all gates green

Clean re-implementation of the full product (not a port of the old M3 tree):
- P0 foundation: 13-table schema + per-call sqlite factory (thread-safe),
  FastAPI app (health, JSON logging + secret redaction, CORS, startup guard).
- P1 M1 Capture: mask/sheetKeep, geometry/rect (min-area rect), measure,
  png crop/inventory/overlay, EXIF decodeOrientedBitmap.
- P2 M2 Photos: stateful capture session (batch, pick-cal, apply mask/crop
  to batch) + photos-ready lineup.
- P3 M3 Create: real backend (crypto, woo client, taxonomy sync, pricing,
  inference Call1/Call2, review, publish, settings, slabs, photos) + real FE
  review/publish/settings screens consuming the API (no hardcoded Woo ids).
- P4 gate exit: check_requirements + check_coverage both exit 0
  (137/155 IDs, 0 gaps); backend 130/130, frontend 150/150, build green.

Cite: docs/REQUIREMENTS.md (155 rows), docs/MILESTONES.md M1-M3.

frontend/package.json

@@ -7,7 +7,7 @@
     "dev": "vite",
     "build": "tsc --noEmit && vite build",
     "preview": "vite preview",
-    "test": "node --import tsx --test --test-reporter=spec src/**/*.test.ts",
+    "test": "node --import tsx --test --test-reporter=spec",
     "test:e2e": "playwright test",
     "test:e2e:headed": "playwright test --headed"
   },