feat: Add photo upload component for user and child profiles

- Created reusable PhotoUpload component with avatar preview
- Added photo upload to child create/edit dialog
- Added profile photo upload to settings page
- Show photo preview with fallback icon
- Display camera button for future file upload integration
- Support URL paste for immediate photo display
- Updated API types to support photoUrl field

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

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

maternal-web/components/children/ChildDialog.tsx

@@ -14,6 +14,7 @@ import {
 } from '@mui/material';
 import { Child, CreateChildData } from '@/lib/api/children';
 import { useTranslation } from '@/hooks/useTranslation';
+import { PhotoUpload } from '@/components/common/PhotoUpload';
 
 interface ChildDialogProps {
   open: boolean;
@@ -146,13 +147,12 @@ export function ChildDialog({ open, onClose, onSubmit, child, isLoading = false
             <MenuItem value="other">{t('gender.other')}</MenuItem>
           </TextField>
 
-          <TextField
+          <PhotoUpload
             label={t('dialog.photoUrl')}
-            value={formData.photoUrl}
-            onChange={handleChange('photoUrl')}
-            fullWidth
-            placeholder={t('dialog.photoPlaceholder')}
+            value={formData.photoUrl || ''}
+            onChange={(url) => setFormData({ ...formData, photoUrl: url })}
             disabled={isLoading}
+            size={80}
           />
         </Box>
       </DialogContent>