Fix iOS text color, viewport meta tag, and security improvements

- Add viewport meta tag to prevent iOS zoom/scaling issues
- Fix text color on iOS Safari (explicit text-gray-900 on buttons, inputs, TimePicker5)
- Add session checks to /api/beos, /api/objekte, /api/wetter
- Revert iframe embedding (X-Frame-Options: DENY, SameSite: lax)
- docker-compose.prod.yml: fix DB_PORT=3306 for production
- Add docker-compose.prod.yml, .env.prod.example, dump/import scripts

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

lib/db.ts

@@ -3,6 +3,7 @@ import type { QueryResult } from 'mysql2/promise';
 
 const dbConfig = {
   host: process.env.DB_HOST || 'mydbase_mysql',
+  port: process.env.DB_PORT ? parseInt(process.env.DB_PORT) : 3306,
   user: process.env.DB_USER,
   password: process.env.DB_PASS,
   database: process.env.DB_NAME || 'logbuch',