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>

app/api/objekte/route.ts

@@ -1,7 +1,10 @@
 import { NextResponse } from 'next/server';
 import { query } from '@/lib/db';
+import { getSession } from '@/lib/session';
 
 export async function GET() {
+  const session = await getSession();
+  if (!session) return NextResponse.json({ error: 'Nicht angemeldet' }, { status: 401 });
   try {
     const rows = await query('SELECT ID, Name FROM objekte ORDER BY LastUsed DESC LIMIT 100');
     return NextResponse.json(rows);