fix: set TZ=Europe/Prague so new Date() returns local Czech time

Server was using UTC — clock-in at 7:45 CET was stored as 6:45 UTC.
MySQL DATETIME columns store values without timezone, so the UTC
value was saved as-is, appearing 1 hour behind.

Now new Date() returns CET/CEST time, matching the PHP behavior.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/config/env.ts

@@ -1,6 +1,9 @@
 import dotenv from 'dotenv';
 dotenv.config();
 
+// Set timezone for Date operations — all attendance/time records are in Czech local time
+process.env.TZ = process.env.TZ || 'Europe/Prague';
+
 function required(key: string): string {
   const val = process.env[key];
   if (!val) throw new Error(`Missing required env variable: ${key}`);