Add voice input UI components for hands-free tracking

Implemented complete voice input user interface:

**Voice Recording Hook (useVoiceInput):**
- Browser Web Speech API integration
- Real-time speech recognition
- Continuous and interim results
- 10-second auto-timeout
- Error handling for permissions, network, audio issues
- Graceful fallback for unsupported browsers

**Voice Input Button Component:**
- Modal dialog with microphone button
- Animated pulsing microphone when recording
- Real-time transcript display
- Automatic intent classification on completion
- Structured data visualization
- Example commands for user guidance
- Success/error feedback with MUI Alerts
- Confidence level indicators

**Floating Action Button:**
- Always-visible FAB in bottom-right corner
- Quick access from any page
- Auto-navigation to appropriate tracking page
- Snackbar feedback messages
- Mobile-optimized positioning (thumb zone)

**Integration with Tracking Pages:**
- Voice button in feeding page header
- Auto-fills form fields from voice commands
- Seamless voice-to-form workflow
- Example: "Fed baby 120ml" → fills bottle type & amount

**Features:**
- ✅ Browser speech recognition (Chrome, Edge, Safari)
- ✅ Real-time transcription display
- ✅ Automatic intent classification
- ✅ Auto-fill tracking forms
- ✅ Visual feedback (animations, colors)
- ✅ Error handling & user guidance
- ✅ Mobile-optimized design
- ✅ Accessibility support

**User Flow:**
1. Click microphone button (floating or in-page)
2. Speak command: "Fed baby 120 ml"
3. See real-time transcript
4. Auto-classification shows intent & data
5. Click "Use Command"
6. Form auto-fills or activity created

**Browser Support:**
- Chrome ✅
- Edge ✅
- Safari ✅
- Firefox ❌ (Web Speech API not supported)

**Files Created:**
- hooks/useVoiceInput.ts - Speech recognition hook
- components/voice/VoiceInputButton.tsx - Modal input component
- components/voice/VoiceFloatingButton.tsx - FAB for quick access
- app/layout.tsx - Added floating button globally
- app/track/feeding/page.tsx - Added voice button to header

Voice input is now accessible from anywhere in the app, providing
true hands-free tracking for parents.

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

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

maternal-web/app/track/feeding/page.tsx

@@ -48,6 +48,7 @@ import { withErrorBoundary } from '@/components/common/ErrorFallbacks';
 import { useAuth } from '@/lib/auth/AuthContext';
 import { trackingApi, Activity } from '@/lib/api/tracking';
 import { childrenApi, Child } from '@/lib/api/children';
+import { VoiceInputButton } from '@/components/voice/VoiceInputButton';
 import { motion } from 'framer-motion';
 import { formatDistanceToNow } from 'date-fns';
 
@@ -350,9 +351,31 @@ function FeedingTrackPage() {
             <IconButton onClick={() => router.back()} sx={{ mr: 2 }}>
               <ArrowBack />
             </IconButton>
-            <Typography variant="h4" fontWeight="600">
+            <Typography variant="h4" fontWeight="600" sx={{ flex: 1 }}>
               Track Feeding
             </Typography>
+            <VoiceInputButton
+              onTranscript={(transcript) => {
+                console.log('[Feeding] Voice transcript:', transcript);
+              }}
+              onClassifiedIntent={(result) => {
+                if (result.intent === 'feeding' && result.structuredData) {
+                  const data = result.structuredData;
+                  // Auto-fill form with voice data
+                  if (data.type === 'bottle' && data.amount) {
+                    setFeedingType('bottle');
+                    setAmount(data.amount.toString());
+                  } else if (data.type?.includes('breast')) {
+                    setFeedingType('breast');
+                    if (data.side) setSide(data.side);
+                    if (data.duration) setDuration(data.duration.toString());
+                  } else if (data.type === 'solid') {
+                    setFeedingType('solid');
+                  }
+                }
+              }}
+              size="medium"
+            />
           </Box>
 
           {error && (