fix(phase2): resolve code quality issues in ItemPhotoUpload (act warnings, toast cleanup, dual error handling)

Fixed 3 critical code quality issues:

1. Act() warnings in tests (9 tests):
   - Wrapped all async state updates in act() blocks in usePhotoUpload.test.ts
   - Tests using waitFor() now properly await state updates within act()
   - All 21 tests pass with zero act() warnings

2. Missing toast cleanup on unmount:
   - Added toastIdRef to track pending toast IDs
   - Added cleanup useEffect that dismisses toasts on component unmount
   - Prevents memory leaks and orphaned toast notifications

3. Dual error reporting channels (lines 23-28):
   - Removed useEffect that synced hook error to local state AND called onError callback
   - Now syncs hook error to local state only (for display)
   - Parent components rely on hook error state, reducing dual-path confusion
   - Toast error calls are explicit in catch block

Test Results:
- Frontend: 312/312 tests passing (includes 21 photo upload tests)
- Act() warnings: Eliminated
- No regressions introduced

frontend/tests/hooks/usePhotoUpload.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect, vi, beforeEach } from 'vitest'
-import { renderHook, waitFor } from '@testing-library/react'
+import { renderHook, waitFor, act } from '@testing-library/react'
 import { usePhotoUpload } from '@/hooks/usePhotoUpload'
 import * as api from '@/lib/api'
 
@@ -36,7 +36,10 @@ describe('usePhotoUpload Hook', () => {
     const { result } = renderHook(() => usePhotoUpload())
 
     const file = new File(['test'], 'test.jpg', { type: 'image/jpeg' })
-    const photo = await result.current.upload(file, 123)
+    let photo
+    await act(async () => {
+      photo = await result.current.upload(file, 123)
+    })
 
     expect(photo).toEqual(mockPhoto)
     expect(result.current.error).toBe(null)
@@ -50,16 +53,16 @@ describe('usePhotoUpload Hook', () => {
       type: 'image/jpeg',
     })
 
-    try {
-      await result.current.upload(largeFile, 123)
-    } catch (error) {
-      // Expected to throw
-    }
-
-    await waitFor(() => {
-      expect(result.current.error).toBeTruthy()
-      expect(result.current.error).toMatch(/File too large/)
+    await act(async () => {
+      try {
+        await result.current.upload(largeFile, 123)
+      } catch (error) {
+        // Expected to throw
+      }
     })
+
+    expect(result.current.error).toBeTruthy()
+    expect(result.current.error).toMatch(/File too large/)
   })
 
   it('should reject invalid MIME types', async () => {
@@ -67,16 +70,16 @@ describe('usePhotoUpload Hook', () => {
 
     const invalidFile = new File(['test'], 'test.txt', { type: 'text/plain' })
 
-    try {
-      await result.current.upload(invalidFile, 123)
-    } catch (error) {
-      // Expected to throw
-    }
-
-    await waitFor(() => {
-      expect(result.current.error).toBeTruthy()
-      expect(result.current.error).toMatch(/Invalid image format/)
+    await act(async () => {
+      try {
+        await result.current.upload(invalidFile, 123)
+      } catch (error) {
+        // Expected to throw
+      }
     })
+
+    expect(result.current.error).toBeTruthy()
+    expect(result.current.error).toMatch(/Invalid image format/)
   })
 
   it('should set isLoading to true during upload', async () => {
@@ -90,14 +93,19 @@ describe('usePhotoUpload Hook', () => {
     const { result } = renderHook(() => usePhotoUpload())
 
     const file = new File(['test'], 'test.jpg', { type: 'image/jpeg' })
-    const uploadPromiseResult = result.current.upload(file, 123)
+    let uploadPromiseResult
+    await act(async () => {
+      uploadPromiseResult = result.current.upload(file, 123)
+    })
 
     await waitFor(() => {
       expect(result.current.isLoading).toBe(true)
     })
 
-    resolveUpload({ status: 'ok', photo: {} })
-    await uploadPromiseResult
+    await act(async () => {
+      resolveUpload({ status: 'ok', photo: {} })
+      await uploadPromiseResult
+    })
 
     await waitFor(() => {
       expect(result.current.isLoading).toBe(false)
@@ -127,7 +135,10 @@ describe('usePhotoUpload Hook', () => {
       const { result } = renderHook(() => usePhotoUpload())
       const file = new File(['test'], `test.${format.ext}`, { type: format.type })
 
-      const photo = await result.current.upload(file, 123)
+      let photo
+      await act(async () => {
+        photo = await result.current.upload(file, 123)
+      })
 
       expect(photo).toEqual(mockPhoto)
       expect(result.current.error).toBe(null)
@@ -143,16 +154,16 @@ describe('usePhotoUpload Hook', () => {
 
     const file = new File(['test'], 'test.jpg', { type: 'image/jpeg' })
 
-    try {
-      await result.current.upload(file, 123)
-    } catch (error) {
-      // Expected to throw
-    }
-
-    await waitFor(() => {
-      expect(result.current.error).toBeTruthy()
-      expect(result.current.error).toMatch(/Network error/)
+    await act(async () => {
+      try {
+        await result.current.upload(file, 123)
+      } catch (error) {
+        // Expected to throw
+      }
     })
+
+    expect(result.current.error).toBeTruthy()
+    expect(result.current.error).toMatch(/Network error/)
   })
 
   it('should reset error state on successful upload', async () => {
@@ -170,7 +181,9 @@ describe('usePhotoUpload Hook', () => {
     const { result } = renderHook(() => usePhotoUpload())
 
     const file = new File(['test'], 'test.jpg', { type: 'image/jpeg' })
-    await result.current.upload(file, 123)
+    await act(async () => {
+      await result.current.upload(file, 123)
+    })
 
     expect(result.current.error).toBe(null)
   })
@@ -190,7 +203,10 @@ describe('usePhotoUpload Hook', () => {
     const { result } = renderHook(() => usePhotoUpload())
 
     const file = new File(['test'], 'test.jpg', { type: 'image/jpeg' })
-    const uploadedPhoto = await result.current.upload(file, 123)
+    let uploadedPhoto
+    await act(async () => {
+      uploadedPhoto = await result.current.upload(file, 123)
+    })
 
     expect(uploadedPhoto).toHaveProperty('thumbnail_url')
     expect(uploadedPhoto).toHaveProperty('full_url')