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/lib/api/photos.ts

@@ -0,0 +1,48 @@
+import apiClient from './client';
+
+export interface PhotoUploadResult {
+  photo: {
+    id: string;
+    url: string;
+    thumbnailUrl?: string;
+    originalUrl?: string;
+    storageKey: string;
+  };
+}
+
+export const photosApi = {
+  /**
+   * Upload a photo for profile/child
+   * Uses multipart/form-data to send file to backend
+   * Backend handles image optimization via Sharp and storage via MinIO
+   */
+  uploadPhoto: async (
+    file: File,
+    options?: {
+      childId?: string;
+      type?: string;
+      caption?: string;
+    }
+  ): Promise<PhotoUploadResult> => {
+    const formData = new FormData();
+    formData.append('photo', file);
+
+    if (options?.childId) {
+      formData.append('childId', options.childId);
+    }
+    if (options?.type) {
+      formData.append('type', options.type);
+    }
+    if (options?.caption) {
+      formData.append('caption', options.caption);
+    }
+
+    const response = await apiClient.post('/api/v1/photos/upload', formData, {
+      headers: {
+        'Content-Type': 'multipart/form-data',
+      },
+    });
+
+    return response.data.data;
+  },
+};