feat: Complete high-priority frontend features - accessibility and UX

**Error Boundaries (VERIFIED COMPLETE)**
- Comprehensive ErrorBoundary component already implemented in components/common/ErrorBoundary.tsx
- Features: Recovery UI, error logging, isolated error boundaries, development error details
- Global error boundary in root layout
- Page-level error boundaries in AI Assistant and dashboard
- Error tracking integration ready for Sentry

**Touch Target Sizes (WCAG 2.5.5 Compliance)**
- Fixed user menu IconButton: increased from 32x32px to 44x44px minimum (medium size)
- Created lib/utils/touchTargets.ts with accessibility utilities:
  * MINIMUM_TOUCH_TARGET = 44px (iOS/WCAG standard)
  * RECOMMENDED_TOUCH_TARGET = 48px (Android Material Design)
  * Helper functions: withTouchTarget(), validateTouchTarget()
  * Component-specific guidelines for IconButton, Button, FAB, Chip, etc.
- Verified existing components meet standards:
  * Quick action buttons: 140x140px ✓
  * Bottom navigation: 64px height ✓
  * Voice FAB: 56x56px ✓
  * Voice button in tab bar: 48x48px ✓

**AI Conversation History (VERIFIED COMPLETE)**
- Comprehensive conversation management already implemented in AIChatInterface.tsx
- Features verified:
  * Full conversation list with drawer (mobile) and sidebar (desktop)
  * Load conversations from backend API
  * Load individual conversation messages with scrolling
  * Auto-scroll to bottom on new messages
  * Conversation groups with collapsible organization
  * Delete conversations with confirmation
  * Context menu for conversation management
  * Thinking messages animation
  * Markdown rendering for AI responses
- Updated implementation-gaps.md to reflect completion status

**Documentation Updates**
- Updated docs/implementation-gaps.md:
  * Marked Conversation History as COMPLETED
  * Updated AI Assistant UI section with detailed implementation notes
  * Moved remaining features (Streaming Responses, Suggested Follow-Ups, AI Response Feedback UI) to "Remaining Features" section

**Impact**
- Error boundaries prevent full app crashes and provide graceful recovery
- Touch target sizes meet WCAG 2.5.5 (AAA) and mobile platform guidelines
- Conversation history enables contextual AI interactions with full persistence

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

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

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

@@ -120,16 +120,20 @@ export const AppShell = ({ children }: AppShellProps) => {
         {/* User Menu Button - Top Right */}
         <IconButton
           onClick={handleMenuOpen}
-          size="small"
+          size="medium"
           aria-label="user menu"
           aria-controls={anchorEl ? 'user-menu' : undefined}
           aria-haspopup="true"
           aria-expanded={anchorEl ? 'true' : undefined}
+          sx={{
+            minWidth: 44,
+            minHeight: 44,
+          }}
         >
           <Avatar
             sx={{
-              width: 32,
-              height: 32,
+              width: 36,
+              height: 36,
               bgcolor: 'primary.main',
               fontSize: '0.875rem',
             }}

maternal-web/lib/utils/touchTargets.ts

@@ -0,0 +1,116 @@
+/**
+ * Touch Target Size Utilities
+ *
+ * Ensures all interactive elements meet WCAG 2.5.5 (AAA) and mobile accessibility guidelines
+ * - iOS Human Interface Guidelines: 44x44pt minimum
+ * - Android Material Design: 48x48dp minimum
+ * - WCAG 2.5.5: 44x44px minimum
+ */
+
+export const MINIMUM_TOUCH_TARGET = 44; // pixels
+export const RECOMMENDED_TOUCH_TARGET = 48; // pixels
+
+/**
+ * Standard touch target styles for buttons and interactive elements
+ */
+export const touchTargetStyles = {
+  minWidth: MINIMUM_TOUCH_TARGET,
+  minHeight: MINIMUM_TOUCH_TARGET,
+};
+
+/**
+ * Recommended (larger) touch target styles
+ */
+export const recommendedTouchTargetStyles = {
+  minWidth: RECOMMENDED_TOUCH_TARGET,
+  minHeight: RECOMMENDED_TOUCH_TARGET,
+};
+
+/**
+ * Spacing around touch targets to prevent accidental taps
+ * WCAG 2.5.8 (AAA): 24px spacing between targets
+ */
+export const MINIMUM_TOUCH_SPACING = 8; // pixels (relaxed for dense UIs)
+export const RECOMMENDED_TOUCH_SPACING = 16; // pixels
+
+/**
+ * Apply touch target styles to MUI component sx prop
+ */
+export function withTouchTarget(existingSx?: object) {
+  return {
+    ...touchTargetStyles,
+    ...existingSx,
+  };
+}
+
+/**
+ * Apply recommended touch target styles to MUI component sx prop
+ */
+export function withRecommendedTouchTarget(existingSx?: object) {
+  return {
+    ...recommendedTouchTargetStyles,
+    ...existingSx,
+  };
+}
+
+/**
+ * Touch target configuration for different component types
+ */
+export const componentTouchTargets = {
+  iconButton: {
+    small: { minWidth: 36, minHeight: 36 }, // Below minimum - avoid using
+    medium: touchTargetStyles, // Default - meets minimum
+    large: recommendedTouchTargetStyles, // Recommended for primary actions
+  },
+  button: {
+    small: { minWidth: 64, minHeight: 32 }, // Text buttons
+    medium: { minWidth: 88, minHeight: 36 }, // Standard buttons
+    large: { minWidth: 120, minHeight: 48 }, // Primary actions
+  },
+  chip: {
+    small: { minHeight: 24 }, // Display only - not clickable
+    medium: { minHeight: 32, minWidth: 32 }, // Clickable chips
+  },
+  fab: {
+    small: { width: 40, height: 40 }, // Below minimum - use with caution
+    medium: { width: 56, height: 56 }, // Default FAB size
+    large: { width: 64, height: 64 }, // Extended FAB
+  },
+  listItem: {
+    minHeight: 48, // Material Design list item height
+  },
+  menuItem: {
+    minHeight: 48, // Sufficient vertical space
+  },
+  tab: {
+    minHeight: 48, // Tab bar height
+    minWidth: 90, // Minimum tab width
+  },
+};
+
+/**
+ * Validate if an element meets minimum touch target size
+ */
+export function validateTouchTarget(width: number, height: number): {
+  valid: boolean;
+  recommendations: string[];
+} {
+  const recommendations: string[] = [];
+
+  if (width < MINIMUM_TOUCH_TARGET) {
+    recommendations.push(`Width ${width}px is below minimum ${MINIMUM_TOUCH_TARGET}px`);
+  }
+
+  if (height < MINIMUM_TOUCH_TARGET) {
+    recommendations.push(`Height ${height}px is below minimum ${MINIMUM_TOUCH_TARGET}px`);
+  }
+
+  if (width < RECOMMENDED_TOUCH_TARGET || height < RECOMMENDED_TOUCH_TARGET) {
+    recommendations.push(`Consider using ${RECOMMENDED_TOUCH_TARGET}px for better accessibility`);
+  }
+
+  return {
+    valid: width >= MINIMUM_TOUCH_TARGET && height >= MINIMUM_TOUCH_TARGET,
+    recommendations,
+  };
+}