feat: Integrate photo upload with MinIO storage and Sharp optimization

Now uses the existing infrastructure instead of base64:
- Created photos API client for multipart/form-data upload
- Upload to /api/v1/photos/upload endpoint
- Backend handles Sharp image optimization (resize, compress, format conversion)
- MinIO/S3-compatible storage for scalable file management
- 10MB file size limit (up from 5MB base64)
- Shows upload progress with spinner
- Returns optimized CDN-ready URLs
- Proper error handling with backend validation

Benefits over previous base64 approach:
✅ Images optimized with Sharp (smaller sizes, better quality)
✅ Stored in MinIO (scalable object storage)
✅ CDN-ready URLs for fast delivery
✅ No database bloat from base64 strings
✅ Supports larger files (10MB vs 5MB)
✅ Automatic thumbnail generation
✅ Better performance and scalability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

maternal-web/components/children/ChildDialog.tsx

@@ -153,6 +153,8 @@ export function ChildDialog({ open, onClose, onSubmit, child, isLoading = false
             onChange={(url) => setFormData({ ...formData, photoUrl: url })}
             disabled={isLoading}
             size={80}
+            childId={child?.id}
+            type="profile"
           />
         </Box>
       </DialogContent>