Einstellungen-Seite: .env-Werte in DB (app_state), keine .env mehr

Neue /einstellungen-Seite (Zahnrad im Header) mit allen bisherigen .env-Werten
(Ollama, E-Mail, CalDAV, REST-API), gespeichert in SQLite (app_state, cfg:-Prefix).
Libs lesen per lib/config.js zur Laufzeit statt beim Start -> Aenderungen
wirken sofort, kein Neustart. Bestehende .env wird beim ersten Start einmalig
migriert.

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

lib/caldav.js

@@ -4,7 +4,7 @@
 // creates / updates / deletes events (PUT / DELETE with iCalendar VEVENTs).
 // Auth is HTTP Basic over HTTPS using the same mail account as lib/mailer.
 //
-// Config (env):
+// Config (DB, editable via /einstellungen — see lib/config.js):
 //   CALDAV_URL        full URL of the calendar collection (must end with /)
 //   MAIL_USER         login (shared with mail)
 //   MAIL_PASSWORD     password (shared with mail)
@@ -14,15 +14,18 @@
 // Europe/Berlin. Wall-clock input from the UI is converted with wallToUtc().
 
 const crypto = require('crypto');
+const config = require('./config');
 
 const TZ = 'Europe/Berlin';
 
+// Read fresh on every call so an edit on the /einstellungen page takes effect
+// immediately (values live in the DB now, not in process.env/.env).
 function cfg() {
   return {
-    url: (process.env.CALDAV_URL || '').trim(),
-    user: process.env.MAIL_USER || '',
-    pass: process.env.MAIL_PASSWORD || '',
-    alarmMin: Number(process.env.CALDAV_ALARM_MIN) || 60,
+    url: (config.get('CALDAV_URL') || '').trim(),
+    user: config.get('MAIL_USER') || '',
+    pass: config.get('MAIL_PASSWORD') || '',
+    alarmMin: Number(config.get('CALDAV_ALARM_MIN')) || 60,
   };
 }