feat: implement device login approval system

Add a complete device authentication approval flow that allows users to approve login requests from new devices on their already-authenticated devices.

Core features:
- Create authentication requests when logging in from new devices
- Display pending requests with device info, IP address, and fingerprint phrases
- Approve or deny requests from web interface with real-time notifications
- Support multiple auth request types (authenticate & unlock, unlock only)
- Automatic expiration and cleanup of stale requests

Backend changes:
- Add auth_requests table with proper indexes for efficient queries
- Implement full CRUD API for authentication requests
- Add notification hub integration for real-time updates
- Add device fingerprint phrase generation for security verification

Frontend changes:
- Add AuthRequestApprovalDialog component for approving/denying requests
- Add PendingAuthRequestsPanel component to display and manage pending requests
- Integrate panels into Security and Settings pages
- Add fingerprint wordlist for generating human-readable verification phrases
- Update i18n translations for all supported languages

Security considerations:
- Access code verification to prevent unauthorized access
- Device fingerprint validation for additional security layer
- IP address and country tracking for audit purposes
- Automatic expiration of old requests (15 minutes)
- Only most recent request per device can be approved

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

webapp/src/lib/i18n/locales/en.ts

@@ -1172,7 +1172,22 @@ const en: Record<string, string> = {
   "txt_target": "Target",
   "txt_time": "Time",
   "txt_time_range": "Time range",
-  "txt_remove_domain": "Remove domain"
+  "txt_remove_domain": "Remove domain",
+  "txt_approve_device_login": "Approve device login",
+  "txt_auth_request_approve_message": "Unlock Bitwarden on your device or approve from the web app. Before approving, make sure the fingerprint phrase matches the one below.",
+  "txt_approve": "Approve",
+  "txt_approving": "Approving...",
+  "txt_deny": "Deny",
+  "txt_later": "Later",
+  "txt_pending_device_logins": "Pending device logins",
+  "txt_no_pending_device_logins": "No pending device logins",
+  "txt_fingerprint_phrase": "Fingerprint phrase",
+  "txt_auth_requests_load_failed": "Failed to load device login requests",
+  "txt_auth_request_update_failed": "Failed to update device login request",
+  "txt_auth_request_approved": "Device login approved",
+  "txt_auth_request_denied": "Device login denied",
+  "txt_auth_request_missing_public_key": "Device login request is missing a public key",
+  "txt_ip_address": "IP address"
 };
 
 export default en;