fix: port changes now correctly queue pending restart for all services

Two bugs fixed:

1. calendar_manager and wireguard_manager (port-only) called
   _restart_container immediately in apply_config, bypassing the pending
   restart banner and restarting the container before the docker port
   binding in .env was updated — leaving the service broken until the
   banner was applied manually. apply_config now only updates the config
   file (radicale.conf / wg0.conf); the docker compose restart happens
   via the banner as intended.

2. Port change detection in update_config used `if old_val is not None`
   to guard against triggering on unchanged values. When a service's port
   was never explicitly saved (first time), old_val was None, so the
   pending restart was never queued. Fix: fall back to PORT_DEFAULTS[key]
   so the comparison is always against the effective current value.

Add TestPortChangeDetection (5 tests) covering first-save and multi-service
accumulation cases.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/calendar_manager.py

@@ -478,7 +478,7 @@ class CalendarManager(BaseServiceManager):
             f.write(config_content)
 
     def apply_config(self, config: Dict[str, Any]) -> Dict[str, Any]:
-        """Update radicale config port and restart cell-radicale."""
+        """Update radicale config file. Port changes go through pending restart (docker binding)."""
         restarted = []
         warnings = []
         if 'port' not in config:
@@ -494,8 +494,8 @@ class CalendarManager(BaseServiceManager):
                 ]
                 with open(radicale_conf, 'w') as f:
                     f.writelines(lines)
-                self._restart_container('cell-radicale')
-                restarted.append('cell-radicale')
+                # No immediate restart — docker port binding must be updated first.
+                # The pending restart banner will run docker compose up with updated .env.
         except Exception as e:
             warnings.append(f"radicale config update failed: {e}")
         return {'restarted': restarted, 'warnings': warnings}