refactor: Unify all settings into single Save Preferences button

Simplified the settings page by consolidating all save buttons into one
global "Save Preferences" button at the bottom of the page.

## Changes Made

### Unified Save Handler
- Merged `handleSaveProfile` and `handleSavePreferences` into single `handleSaveAll` function
- Single save handler now updates:
  * Profile name
  * Timezone
  * Time format (12h/24h)
  * Notification preferences
- One API call to save all settings at once

### Removed Individual Save Buttons
- Removed "Save Profile" button from Profile Information section
- Removed "Save Preferences" button from Preferences section
- Removed "Save Notification Settings" button from Notifications section

### Added Global Save Button
- Centered "Save Preferences" button at bottom of settings
- Positioned above Account Actions (Logout) section
- Large, prominent button (minWidth: 200px)
- Single source of truth for all settings changes

### User Experience Benefits
- **Simpler**: One clear action to save all changes
- **Fewer clicks**: No need to save each section separately
- **Clear feedback**: Single success/error message for all updates
- **Better UX**: Users can make multiple changes and save once
- **Consistent**: All settings treated as unified preferences

Files changed: 1 file (settings page)

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

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

maternal-web/app/settings/page.tsx

@@ -56,34 +56,7 @@ export default function SettingsPage() {
     }
   }, [user]);
 
-  const handleSavePreferences = async () => {
+  const handleSaveAll = async () => {
-    setIsLoading(true);
-    setError(null);
-
-    try {
-      const response = await usersApi.updateProfile({
-        timezone,
-        preferences: {
-          ...settings,
-          timeFormat,
-        }
-      });
-      console.log('✅ Preferences updated successfully:', response);
-
-      // Refresh user to get latest data from server
-      await refreshUser();
-
-      setSuccessMessage('Preferences saved successfully!');
-    } catch (err: any) {
-      console.error('❌ Failed to update preferences:', err);
-      console.error('Error response:', err.response);
-      setError(err.response?.data?.message || err.message || 'Failed to save preferences. Please try again.');
-    } finally {
-      setIsLoading(false);
-    }
-  };
-
-  const handleSaveProfile = async () => {
     // Validate name
     if (!name || name.trim() === '') {
       setNameError('Name cannot be empty');
@@ -97,17 +70,22 @@ export default function SettingsPage() {
     try {
       const response = await usersApi.updateProfile({
         name: name.trim(),
+        timezone,
+        preferences: {
+          ...settings,
+          timeFormat,
+        }
       });
-      console.log('✅ Profile updated successfully:', response);
+      console.log('✅ All settings saved successfully:', response);
 
       // Refresh user to get latest data from server
       await refreshUser();
 
-      setSuccessMessage('Profile updated successfully!');
+      setSuccessMessage('Settings saved successfully!');
     } catch (err: any) {
-      console.error('❌ Failed to update profile:', err);
+      console.error('❌ Failed to save settings:', err);
       console.error('Error response:', err.response);
-      setError(err.response?.data?.message || err.message || 'Failed to update profile. Please try again.');
+      setError(err.response?.data?.message || err.message || 'Failed to save settings. Please try again.');
     } finally {
       setIsLoading(false);
     }
@@ -172,15 +150,6 @@ export default function SettingsPage() {
                 disabled
                 helperText="Email cannot be changed"
               />
-              <Button
-                variant="contained"
-                startIcon={isLoading ? <CircularProgress size={20} color="inherit" /> : <Save />}
-                onClick={handleSaveProfile}
-                disabled={isLoading}
-                sx={{ alignSelf: 'flex-start' }}
-              >
-                {isLoading ? 'Saving...' : 'Save Profile'}
-              </Button>
             </Box>
           </CardContent>
         </Card>
@@ -206,15 +175,6 @@ export default function SettingsPage() {
               <Divider />
               <TimeFormatSelector value={timeFormat} onChange={setTimeFormat} />
             </Box>
-            <Button
-              variant="contained"
-              startIcon={isLoading ? <CircularProgress size={20} color="inherit" /> : <Save />}
-              onClick={handleSavePreferences}
-              disabled={isLoading}
-              sx={{ mt: 3, alignSelf: 'flex-start' }}
-            >
-              {isLoading ? 'Saving...' : 'Save Preferences'}
-            </Button>
           </CardContent>
         </Card>
       </motion.div>
@@ -252,15 +212,6 @@ export default function SettingsPage() {
                 label="Email Updates"
               />
             </Box>
-            <Button
-              variant="contained"
-              startIcon={isLoading ? <CircularProgress size={20} color="inherit" /> : <Save />}
-              onClick={handleSavePreferences}
-              disabled={isLoading}
-              sx={{ mt: 2, alignSelf: 'flex-start' }}
-            >
-              {isLoading ? 'Saving...' : 'Save Notification Settings'}
-            </Button>
           </CardContent>
         </Card>
       </motion.div>
@@ -358,6 +309,26 @@ export default function SettingsPage() {
         </Box>
       </motion.div>
 
+      {/* Global Save Button */}
+      <motion.div
+        initial={{ opacity: 0, y: 20 }}
+        animate={{ opacity: 1, y: 0 }}
+        transition={{ duration: 0.4, delay: 0.44 }}
+      >
+        <Box sx={{ mb: 3, display: 'flex', justifyContent: 'center' }}>
+          <Button
+            variant="contained"
+            size="large"
+            startIcon={isLoading ? <CircularProgress size={20} color="inherit" /> : <Save />}
+            onClick={handleSaveAll}
+            disabled={isLoading}
+            sx={{ minWidth: 200 }}
+          >
+            {isLoading ? 'Saving...' : 'Save Preferences'}
+          </Button>
+        </Box>
+      </motion.div>
+
       {/* Account Actions */}
       <motion.div
         initial={{ opacity: 0, y: 20 }}