docs: update SESSION_STATE for Phase 3 Task 4 completion

dev_docs/SESSION_STATE.md

@@ -1,9 +1,91 @@
 # CURRENT AI WORKING SESSION — HANDOVER
 
 **Active AI:** Claude Haiku 4.5
-**Last Updated:** 2026-04-21 (Session 23 - Phase 3 Task 3 Complete)
-**Current Version:** v1.13.1 (Auto-photo-save integration + Phase 3 Task 3 complete)
-**Branch:** dev (All changes committed, ready for Phase 3 Task 4)
+**Last Updated:** 2026-04-21 (Session 24 - Phase 3 Task 4 Complete)
+**Current Version:** v1.13.1 (Auto-photo-save integration + Phase 3 Task 4 complete)
+**Branch:** dev (All changes committed, ready for Phase 3 Task 5)
+
+---
+
+## SESSION 24 SUMMARY — Phase 3 Task 4: Store Extracted Image + Metadata in useAIExtraction Hook
+
+### What Was Done
+
+**Phase 3 Task 4: Store extracted image blob and image_processing metadata — COMPLETE ✅**
+
+1. ✅ **Extended useAIExtraction hook** (`frontend/hooks/useAIExtraction.ts`)
+   - Added `extractedImageBlob` state: stores original image Blob after fetch
+   - Added `setExtractedImageBlob` setter: allows manual control and clearing
+   - Modified `processImage()` to store blob: `setExtractedImageBlob(blob)` after fetch
+   - Returned both from hook for access by callers
+   - extractedItems already includes image_processing metadata from AI response
+
+2. ✅ **Comprehensive test suite** (`frontend/tests/hooks/useAIExtraction.test.ts`)
+   - Test 1: Initialize extractedImageBlob as null ✅
+   - Test 2: Store blob after processImage fetches from data URL ✅
+   - Test 3: Allow manual setExtractedImageBlob ✅
+   - Test 4: Allow clearing extractedImageBlob by setting to null ✅
+   - Test 5: Store extractedItems with image_processing from AI response ✅
+   - Test 6: Preserve image_processing when handling wrapped AI responses ✅
+   - Test 7: Handle multiple items each with independent image_processing ✅
+   - Test 8: Store both blob and image_processing for use in photo upload ✅
+   - Test 9: Maintain blob when extractedItems are updated ✅
+   - Test 10: Clear extractedImageBlob when resetting extracted items ✅
+   - Test 11: Allow resetting image without affecting blob storage ✅
+   - Test 12: Not set extractedImageBlob if fetch fails ✅
+   - Test 13: Not set extractedImageBlob if blob conversion fails ✅
+   - Test 14: Provide extractedImageBlob as FormData-ready Blob for later photo upload ✅
+   - Test 15: Preserve blob size and type for upload validation ✅
+   - All 15 tests passing ✅
+
+3. ✅ **Full test suite validation**
+   - Frontend: 442/442 tests passing (427 existing + 15 new) ✅
+   - Zero regressions introduced
+   - All hook functionality working correctly
+
+### Key Implementation Details
+
+**Hook State:**
+```typescript
+const [extractedImageBlob, setExtractedImageBlob] = useState<Blob | null>(null);
+```
+
+**In processImage():**
+```typescript
+const blob = await (await fetch(image)).blob();
+setExtractedImageBlob(blob);  // Store for photo upload later
+```
+
+**Returned from hook:**
+```typescript
+return {
+  extractedImageBlob,
+  setExtractedImageBlob,
+  // ... existing returns ...
+}
+```
+
+**What's Available for Photo Upload:**
+- `extractedImageBlob` — Original image as Blob (ready for FormData)
+- `extractedItems[0].image_processing` — {crop_bounds, rotation_degrees, confidence} from AI
+- Both stored after processImage() completes
+- Can be passed to useItemCreate for auto-upload in next task
+
+### Test Results
+- **New Tests:** 15/15 passing ✅
+- **Frontend Suite:** 442/442 passing (zero regressions) ✅
+- **Commit:** `d73b7e45` (feat: store extracted image blob and image_processing metadata in useAIExtraction hook)
+
+### Files Modified/Created
+- `frontend/hooks/useAIExtraction.ts` — Added extractedImageBlob state and storage
+- `frontend/tests/hooks/useAIExtraction.test.ts` — NEW: Comprehensive test suite (15 tests)
+
+### What's Next (Phase 3 Task 5+)
+- Task 5: Auto-upload photo in useItemCreate hook
+- Task 6: Update AIOnboarding component
+- Task 7: Backend integration tests (full flow)
+- Task 8: Frontend E2E test
+- Task 9: Documentation update
 
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