fix: health history all-down — connectivity checks and UI data path

Service manager fixes (connectivity tests):
- email_manager: replace telnet with socket.create_connection for SMTP/IMAP;
  replace nslookup with socket.getaddrinfo for DNS; exclude unconfigured domain
  from success (email healthy=False now correctly means ports refused, not missing domain)
- calendar_manager: replace localhost:5232 with cell-radicale:5232;
  fix database check to test dir writability instead of file existence (files created on demand)
- file_manager: replace localhost:8080 with cell-webdav:80; add top-level success key
- network_manager: replace nslookup with socket.getaddrinfo;
  add success key to dhcp_test and ntp_test return values
- routing_manager: exclude iptables_access from success
  (iptables runs in cell-wireguard, not API container)
- wireguard_manager: add success key to no-arg test_connectivity result

Health history UI:
- SvcCol reads data?.status?.running || data?.status?.status — handles nested health check shape

Result: network/wireguard/calendar/files/routing/vault all healthy=True.
Email healthy=False is correct — mail server needs ≥1 account before Dovecot starts.

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

api/file_manager.py

@@ -29,7 +29,7 @@ class FileManager(BaseServiceManager):
         self.safe_makedirs(self.webdav_dir)
         
         # WebDAV service URL
-        self.webdav_url = 'http://localhost:8080'
+        self.webdav_url = 'http://cell-webdav:80'
         
         # Initialize WebDAV configuration
         self._ensure_config_exists()
@@ -411,10 +411,12 @@ umask = 022
                     'message': str(e)
                 }
             
+            results['success'] = results.get('http', {}).get('success', False)
             return results
-            
+
         except Exception as e:
             return {
+                'success': False,
                 'http': {'success': False, 'message': str(e)},
                 'webdav': {'success': False, 'message': str(e)}
             }