feat: Add user profile photo upload with base64 encoding

Added complete photo upload support for user profiles:
- Added photoUrl field to User entity and all auth responses
- Created migration V008 for photo_url column in users table
- Updated UpdateProfileDto to include photoUrl validation
- Modified auth.service.ts to handle photoUrl in all user responses (register, login, getUserById, updateProfile, refreshAccessToken, loginWithExternalAuth)
- Updated AuthResponse interface to include photoUrl
- Updated frontend User and UserProfile interfaces to include photoUrl
- Updated AppShell to display user photoUrl in header avatar
- Fixed ChildDialog to remove invalid props from PhotoUpload component

The photo upload uses base64 encoding (max 5MB) for simplicity and works across all environments. Future enhancement can migrate to CDN/object storage.

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

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

maternal-web/components/children/ChildDialog.tsx

@@ -153,8 +153,6 @@ 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>

maternal-web/components/layouts/AppShell/AppShell.tsx

@@ -116,6 +116,7 @@ export const AppShell = ({ children }: AppShellProps) => {
             }}
           >
             <Avatar
+              src={user?.photoUrl}
               sx={{
                 width: 36,
                 height: 36,

maternal-web/lib/api/users.ts

@@ -17,6 +17,7 @@ export interface UserProfile {
   id: string;
   email: string;
   name: string;
+  photoUrl?: string;
   role: string;
   locale: string;
   emailVerified: boolean;

maternal-web/lib/auth/AuthContext.tsx

@@ -9,6 +9,7 @@ export interface User {
   id: string;
   email: string;
   name: string;
+  photoUrl?: string;
   role: string;
   families?: Array<{
     id: string;