Fix caldav-sync.js imports to match Task 2 spec

Remove buildICS, escapeICS, unescapeICS imports - these will be
needed in Task 5 (Sync Functions), not in Task 2. Keep only the
4 functions specified in the Task 2 spec: parseICS, formatICSDate,
tzLocalToUTC, applyDuration.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

server/services/caldav-sync.js

@@ -12,9 +12,6 @@ import * as db from '../db.js';
 // Reused functions from apple-calendar.js
 import {
   parseICS,
-  buildICS,
-  escapeICS,
-  unescapeICS,
   formatICSDate,
   tzLocalToUTC,
   applyDuration