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/routing_manager.py

@@ -575,7 +575,8 @@ class RoutingManager(BaseServiceManager):
                 'iptables_access': iptables_test,
                 'network_interfaces': interfaces_test,
                 'routing_table_access': routing_table_test,
-                'success': routing_test.get('success', False) and iptables_test.get('success', False),
+                # iptables runs in cell-wireguard, not API container — exclude from success
+                'success': routing_test.get('success', False),
                 'timestamp': datetime.utcnow().isoformat()
             }