feat: add contacts phase 2, advanced search, vacation responder, Docker & TOTP 2FA

- Contact groups/lists, vCard import/export (RFC 6350), bulk operations
- Advanced search with JMAP filter panel, search chips, cross-mailbox queries
- Vacation responder with JMAP VacationResponse, settings tab, sidebar indicator
- TOTP two-factor authentication support
- Docker multi-stage build with standalone output and docker-compose
- CSP Report-Only headers and security headers via proxy middleware
- Virtual scrolling for large email lists
- Structured server-side logger (text/JSON, configurable level)
- 450+ tests (contacts, vCard, threads, headers, identity, components)
- Playwright E2E framework setup
- Updated README and ROADMAP with all new features

app/api/config/route.ts

@@ -1,4 +1,5 @@
 import { NextResponse } from 'next/server';
+import { logger } from '@/lib/logger';
 
 /**
  * Runtime configuration endpoint
@@ -13,6 +14,7 @@ import { NextResponse } from 'next/server';
  * 3. Default values
  */
 export async function GET() {
+  logger.debug('Config requested');
   return NextResponse.json({
     appName: process.env.APP_NAME || process.env.NEXT_PUBLIC_APP_NAME || 'Webmail',
     jmapServerUrl: process.env.JMAP_SERVER_URL || process.env.NEXT_PUBLIC_JMAP_SERVER_URL || '',