feat: Complete high-priority i18n localization with date/time support

This commit implements comprehensive localization for high-priority components:

## Tracking Pages (4 files)
- Localized feeding, sleep, diaper, and medicine tracking pages
- Replaced hardcoded strings with translation keys from tracking namespace
- Added useTranslation hook integration
- All form labels, buttons, and messages now support multiple languages

## Child Dialog Components (2 files)
- Localized ChildDialog (add/edit child form)
- Localized DeleteConfirmDialog
- Added new translation keys to children.json for dialog content
- Includes validation messages and action buttons

## Date/Time Localization (14 files + new hook)
- Created useLocalizedDate hook wrapping date-fns with locale support
- Supports 5 languages: English, Spanish, French, Portuguese, Chinese
- Updated all date formatting across:
  * Tracking pages (feeding, sleep, diaper, medicine)
  * Activity pages (activities, history, track activity)
  * Settings components (sessions, biometric, device trust)
  * Analytics components (insights, growth, sleep chart, feeding graph)
- Date displays automatically adapt to user's language (e.g., "2 hours ago" → "hace 2 horas")

## Translation Updates
- Enhanced children.json with dialog section containing:
  * Form field labels (name, birthDate, gender, photoUrl)
  * Action buttons (add, update, delete, cancel, saving, deleting)
  * Delete confirmation messages
  * Validation error messages

Files changed: 17 files (+164, -113)
Languages supported: en, es, fr, pt-BR, zh-CN

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

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

maternal-web/locales/en/children.json

@@ -13,6 +13,27 @@
     "female": "Female",
     "other": "Other"
   },
+  "dialog": {
+    "name": "Name",
+    "birthDate": "Birth Date",
+    "gender": "Gender",
+    "photoUrl": "Photo URL (Optional)",
+    "photoPlaceholder": "https://example.com/photo.jpg",
+    "cancel": "Cancel",
+    "add": "Add",
+    "update": "Update",
+    "saving": "Saving...",
+    "delete": "Delete",
+    "deleting": "Deleting...",
+    "confirmDelete": "Confirm Delete",
+    "confirmDeleteMessage": "Are you sure you want to delete",
+    "confirmDeleteWarning": "This action cannot be undone. All associated data will be permanently removed.",
+    "validation": {
+      "nameRequired": "Please enter a name",
+      "birthDateRequired": "Please select a birth date",
+      "birthDateFuture": "Birth date cannot be in the future"
+    }
+  },
   "errors": {
     "noFamily": "No family found. Please complete onboarding first.",
     "loadFailed": "Failed to load children",