feat: add getBaseUrl function for consistent base URL generation across routes

feat(calendar): display local timezone in calendar view
feat(i18n): add timezone label to German and English translations

server/routes/caldav.js

@@ -14,6 +14,7 @@ import { Router, text } from 'express';
 import crypto from 'crypto';
 import { getDb } from '../config/database.js';
 import { log } from '../config/logger.js';
+import { getBaseUrl } from '../middleware/auth.js';
 
 const router = Router();
 
@@ -239,12 +240,8 @@ function validateCalDAVUser(req, res, next) {
   next();
 }
 
-// ── Base URL helper ────────────────────────────────────────────────────────
-function baseUrl(req) {
-  const proto = req.get('x-forwarded-proto') || req.protocol;
-  const host = req.get('x-forwarded-host') || req.get('host');
-  return `${proto}://${host}`;
-}
+// ── Base URL helper (uses shared getBaseUrl from auth.js) ──────────────────
+const baseUrl = getBaseUrl;
 
 // ── PROPFIND response builders ─────────────────────────────────────────────