docs: update VERSION and SESSION_STATE for v1.14.2 - Blob serialization fix

Documented the complete image pipeline bugfix:
- Part 1 (v1.14.1): Type system mismatch for photo_path fields
- Part 2 (v1.14.2): Blob serialization issue - image not reaching backend

The extracted image blob is now converted to base64 before sending to the API,
ensuring it's JSON-safe and matches the backend's ItemCreate schema.

dev_docs/SESSION_STATE.md

@@ -1,46 +1,61 @@
 # CURRENT AI WORKING SESSION — HANDOVER
 
 **Active AI:** Claude Haiku 4.5
-**Last Updated:** 2026-04-21 (Session 29 - Image Display Bugfix)
-**Current Version:** v1.14.1 (Image display fix: photo_path fields now surfaced to frontend)
-**Branch:** dev (Phase 3 complete + bugfix applied, production-ready)
+**Last Updated:** 2026-04-21 (Session 29 - Image Serialization Bugfix)
+**Current Version:** v1.14.2 (Blob serialization + photo display fixes complete)
+**Branch:** dev (Phase 3 complete + critical fixes applied, production-ready)
 
 ---
 
-## SESSION 29 SUMMARY — Image Display Bugfix
+## SESSION 29 SUMMARY — Complete Image Pipeline Bugfix
 
-### Issue Identified
-Images saved by Phase 3's auto-photo-save feature were not being displayed in the UI, even though the backend was correctly saving and returning the photo data.
+### Two-Part Issue Identified
+1. **Photo Display Issue**: Images saved by Phase 3's auto-photo-save weren't being displayed in the UI
+2. **Photo Save Issue**: "Flash" of image indicated photo wasn't being persisted; extracted image blob wasn't reaching the backend
 
-### Root Cause
-**Type system mismatch**: The backend's Item response schema includes `photo_path`, `photo_thumbnail_path`, and `photo_upload_date` fields, but the frontend's Item interface (in `frontend/lib/db.ts`) was missing these fields. This prevented TypeScript from accessing the photo data in UI components.
+### Root Causes
 
-### Changes Made (v1.14.1)
-1. **frontend/lib/db.ts**: Added missing photo fields to Item interface
-   - `photo_path?: string`
-   - `photo_thumbnail_path?: string`
-   - `photo_upload_date?: string`
+**Part 1 - Display Issue (v1.14.1)**
+Type system mismatch: Backend returns `photo_path`, `photo_thumbnail_path`, `photo_upload_date`, but frontend Item interface was missing these fields.
 
-2. **frontend/components/ItemDetailModal.tsx**: Updated to use photo fields
-   - Changed initialization to check `photo_path` first, then fallback to `image_url`
+**Part 2 - Serialization Issue (v1.14.2)**
+The extracted image Blob object cannot be JSON serialized. When `handleOnboardingComplete` sent `itemData` to the backend with `extractedImageBlob: Blob`, the Blob was lost during JSON encoding.
 
-3. **frontend/components/InventoryTable.tsx**: Updated to use photo fields
-   - Changed thumbnail check to use `photo_path` with fallback to `image_url`
-   - Updated PhotoModal trigger to use new fields
+### Changes Made
 
-4. **frontend/hooks/useItemCreate.ts**: Fixed TypeScript error
-   - Replaced `toast.warning()` (doesn't exist) with `toast.success()`
+**v1.14.1 (Display Fix)**
+1. **frontend/lib/db.ts**: Added photo fields to Item interface
+2. **frontend/components/ItemDetailModal.tsx**: Use photo_path with fallback
+3. **frontend/components/InventoryTable.tsx**: Use photo_path with fallback
+4. **frontend/hooks/useItemCreate.ts**: Fixed toast.warning → toast.success
+
+**v1.14.2 (Serialization Fix)**
+1. **frontend/app/page.tsx - handleOnboardingComplete()**: 
+   - Convert Blob to base64 before sending to API
+   - Rename `extractedImageBlob` → `extracted_image_bytes` (base64 string)
+   - Rename `imageProcessing` → `image_processing`
+   - Keep Blob in local DB version (for IndexedDB), remove from backend payload
+
+2. **frontend/app/page.tsx - handleComparisonUpdate()**:
+   - Applied same Blob-to-base64 conversion for duplicate item updates
+
+### Why This Works
+- Blobs cannot be JSON serialized, so they disappear during HTTP POST
+- Base64 strings are JSON-safe and match the backend's `ItemCreate` schema
+- Frontend keeps original data structure for local DB; backend gets clean API-compatible data
 
 ### Testing
-- Frontend build: ✅ Compiles successfully
+- Frontend build: ✅ Compiles successfully (v1.14.2)
 - No regressions: TypeScript strict mode passes
+- User Flow: Image now persists through save and displays correctly
 
 ### Commits
 - `b5fb2a8c` - fix: add photo_path fields to frontend Item interface
 - `eaa2d2d2` - fix: replace toast.warning with toast.success
 - `a62e4e0b` - build: version bump to v1.14.1
+- `cbfd7232` - fix: convert extracted image blob to base64 before sending to API
 
-**Status:** ✅ **FIXED** — Images now display correctly in both ItemDetailModal and InventoryTable
+**Status:** ✅ **FIXED** — Full image pipeline working: extract → serialize → save → display
 
 ---