refactor: extract common functions to utils

- Add get_redis_client() to calendar_sync_utils.py
- Add get_advoware_employees() to calendar_sync_utils.py
- Add set_employee_lock() and clear_employee_lock() to calendar_sync_utils.py
- Update all step files to use shared utility functions
- Remove duplicate code across calendar_sync_*.py files

bitbylaw/steps/advoware_cal_sync/calendar_sync_api_step.py

@@ -1,6 +1,7 @@
 import json
 import redis
 from config import Config
+from .calendar_sync_utils import get_redis_client, set_employee_lock
 
 config = {
     'type': 'api',
@@ -50,14 +51,9 @@ async def handler(req, context):
             employee_lock_key = f'calendar_sync_lock_{kuerzel_upper}'
 
             # Prüfe ob bereits ein Sync für diesen Mitarbeiter läuft
-            redis_client = redis.Redis(
-                host=Config.REDIS_HOST,
-                port=int(Config.REDIS_PORT),
-                db=int(Config.REDIS_DB_CALENDAR_SYNC),
-                socket_timeout=Config.REDIS_TIMEOUT_SECONDS
-            )
+            redis_client = get_redis_client(context)
             
-            if redis_client.set(employee_lock_key, 'api', ex=1800, nx=True) is None:
+            if not set_employee_lock(redis_client, kuerzel_upper, 'api', context):
                 context.logger.info(f"Calendar Sync API: Sync bereits aktiv für {kuerzel_upper}, überspringe")
                 return {
                     'status': 409,