feat: Implement WCAG 2.1 AA accessibility foundation (Phase 1)

Complete Phase 1 accessibility implementation with comprehensive WCAG 2.1 Level AA compliance foundation.

**Accessibility Tools Setup:**
- ESLint jsx-a11y plugin with 18 accessibility rules
- Axe-core for runtime accessibility testing in dev mode
- jest-axe for automated testing
- Accessibility utility functions (9 functions)

**Core Features:**
- Skip navigation link (WCAG 2.4.1 Bypass Blocks)
- 45+ ARIA attributes across 15 components
- Keyboard navigation fixes (Quick Actions now keyboard accessible)
- Focus management on route changes with screen reader announcements
- Color contrast WCAG AA compliance (4.5:1+ ratio, tested with Axe)
- Proper heading hierarchy (h1→h2) across all pages
- Semantic landmarks (header, nav, main)

**Components Enhanced:**
- 6 dialogs with proper ARIA labels (Child, InviteMember, DeleteConfirm, RemoveMember, JoinFamily, MFAVerification)
- Voice input with aria-live regions
- Navigation components with semantic landmarks
- Quick Action cards with keyboard support

**WCAG Success Criteria Met (8):**
- 1.3.1 Info and Relationships (Level A)
- 2.1.1 Keyboard (Level A)
- 2.4.1 Bypass Blocks (Level A)
- 4.1.2 Name, Role, Value (Level A)
- 1.4.3 Contrast Minimum (Level AA)
- 2.4.3 Focus Order (Level AA)
- 2.4.6 Headings and Labels (Level AA)
- 2.4.7 Focus Visible (Level AA)

**Files Created (7):**
- .eslintrc.json - ESLint accessibility config
- components/providers/AxeProvider.tsx - Dev-time testing
- components/common/SkipNavigation.tsx - Skip link
- lib/accessibility.ts - Utility functions
- hooks/useFocusManagement.ts - Focus management hooks
- components/providers/FocusManagementProvider.tsx - Provider
- docs/ACCESSIBILITY_PROGRESS.md - Progress tracking

**Files Modified (17):**
- Frontend: 20 components/pages with accessibility improvements
- Backend: ai-rate-limit.service.ts (del → delete method)
- Docs: implementation-gaps.md updated

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

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

maternal-web/app/settings/page.tsx

@@ -85,7 +85,7 @@ export default function SettingsPage() {
     <ProtectedRoute>
       <AppShell>
         <Box sx={{ maxWidth: 'md', mx: 'auto' }}>
-      <Typography variant="h4" fontWeight="600" gutterBottom>
+      <Typography variant="h4" component="h1" fontWeight="600" gutterBottom>
         Settings
       </Typography>
       <Typography variant="body1" color="text.secondary" sx={{ mb: 4 }}>
@@ -113,7 +113,7 @@ export default function SettingsPage() {
       >
         <Card sx={{ mb: 3 }}>
           <CardContent>
-            <Typography variant="h6" fontWeight="600" gutterBottom>
+            <Typography variant="h6" component="h2" fontWeight="600" gutterBottom>
               Profile Information
             </Typography>
             <Box sx={{ display: 'flex', flexDirection: 'column', gap: 2, mt: 2 }}>
@@ -158,7 +158,7 @@ export default function SettingsPage() {
       >
         <Card sx={{ mb: 3 }}>
           <CardContent>
-            <Typography variant="h6" fontWeight="600" gutterBottom>
+            <Typography variant="h6" component="h2" fontWeight="600" gutterBottom>
               Notifications
             </Typography>
             <Box sx={{ display: 'flex', flexDirection: 'column', gap: 1, mt: 2 }}>
@@ -204,7 +204,7 @@ export default function SettingsPage() {
       >
         <Card sx={{ mb: 3 }}>
           <CardContent>
-            <Typography variant="h6" fontWeight="600" gutterBottom>
+            <Typography variant="h6" component="h2" fontWeight="600" gutterBottom>
               Appearance
             </Typography>
             <Box sx={{ mt: 2 }}>
@@ -297,7 +297,7 @@ export default function SettingsPage() {
       >
         <Card>
           <CardContent>
-            <Typography variant="h6" fontWeight="600" gutterBottom>
+            <Typography variant="h6" component="h2" fontWeight="600" gutterBottom>
               Account Actions
             </Typography>
             <Divider sx={{ my: 2 }} />