De-hardcode ticket URL and cluster name; improve diagnostic polling UX

app.py:
- Context processor injects config.ticket_api.web_url into all templates
  (falls back to 'http://t.lotusguild.org/ticket/' if not set in config)

templates/base.html:
- Inject GANDALF_CONFIG JS global with ticket_web_url before app.js loads

static/app.js:
- Use GANDALF_CONFIG.ticket_web_url instead of hardcoded domain

templates/index.html:
- Use {{ config.ticket_api.web_url }} Jinja var instead of hardcoded domain

monitor.py:
- CLUSTER_NAME constant kept as default; NetworkMonitor now reads cluster_name
  from config monitor.cluster_name, falling back to the constant
- All CLUSTER_NAME references inside class methods replaced with self.cluster_name

templates/inspector.html:
- pollDiagnostic() .catch() now clears interval and shows error message instead
  of silently ignoring network failures during active polling

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

monitor.py

@@ -641,6 +641,7 @@ class NetworkMonitor:
         self.poll_interval = mon.get('poll_interval', 120)
         self.fail_thresh = mon.get('failure_threshold', 2)
         self.cluster_thresh = mon.get('cluster_threshold', 3)
+        self.cluster_name = mon.get('cluster_name', CLUSTER_NAME)
 
         # Build Prometheus instance → hostname lookup
         self._instance_map: Dict[str, str] = {
@@ -706,13 +707,13 @@ class NetworkMonitor:
             sup = db.check_suppressed(suppressions, 'all', '')
             event_id, is_new, consec = db.upsert_event(
                 'cluster_network_issue', 'critical', 'prometheus',
-                CLUSTER_NAME, '',
+                self.cluster_name, '',
                 f'{len(hosts_with_regression)} hosts reporting simultaneous interface failures: '
                 f'{", ".join(hosts_with_regression)}',
             )
             if not sup and is_new:
                 title = (
-                    f'[{CLUSTER_NAME}][auto][production][issue][network][cluster-wide] '
+                    f'[{self.cluster_name}][auto][production][issue][network][cluster-wide] '
                     f'Multiple hosts reporting interface failures'
                 )
                 desc = (
@@ -728,7 +729,7 @@ class NetworkMonitor:
                 if tid:
                     db.set_ticket_id(event_id, tid)
         else:
-            db.resolve_event('cluster_network_issue', CLUSTER_NAME, '')
+            db.resolve_event('cluster_network_issue', self.cluster_name, '')
 
     def _ticket_interface(
         self, event_id: int, is_new: bool, host: str, iface: str, consec: int