Fix misleading docstring on _purge_old_jobs_loop

The comment claimed the function "runs daily event purge" — that
housekeeping is done by monitor.py's main loop, not here.

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

app.py

@@ -64,7 +64,7 @@ _diag_rate: dict = {}
 
 
 def _purge_old_jobs_loop():
-    """Background thread: remove stale diag jobs and run daily event purge."""
+    """Background thread: remove stale diagnostic jobs and mark stuck ones done."""
     while True:
         time.sleep(120)
         cutoff = time.time() - 600

monitor.py

@@ -837,10 +837,10 @@ class NetworkMonitor:
     # ------------------------------------------------------------------
     # Ping-only hosts (no node_exporter)
     # ------------------------------------------------------------------
-    def _process_ping_hosts(self, suppressions: list) -> None:
+    def _process_ping_hosts(self, suppressions: list, ping_states: Dict[str, bool]) -> None:
         for h in self.cfg.get('monitor', {}).get('ping_hosts', []):
             name, ip = h['name'], h['ip']
-            reachable = self.pulse.ping(ip)
+            reachable = ping_states.get(name, False)
 
             if not reachable:
                 sup = db.check_suppressed(suppressions, 'host', name)
@@ -882,6 +882,7 @@ class NetworkMonitor:
     def _collect_snapshot(
         self, iface_states: Dict[str, Dict[str, bool]],
         unifi_devices: Optional[List[dict]] = None,
+        ping_states: Optional[Dict[str, bool]] = None,
     ) -> dict:
         # Accept pre-fetched devices; fall back to empty list if unavailable
         display_unifi = unifi_devices if unifi_devices is not None else []
@@ -910,7 +911,7 @@ class NetworkMonitor:
 
         for h in self.cfg.get('monitor', {}).get('ping_hosts', []):
             name, ip = h['name'], h['ip']
-            reachable = self.pulse.ping(ip, count=1, timeout=2)
+            reachable = (ping_states or {}).get(name, False)
             hosts[name] = {
                 'ip': ip,
                 'interfaces': {},
@@ -942,8 +943,14 @@ class NetworkMonitor:
                 # 2. Fetch UniFi devices once — used by both snapshot and alert processing
                 unifi_devices = self.unifi.get_devices()
 
-                # 3. Collect and store snapshot for dashboard
-                snapshot = self._collect_snapshot(iface_states, unifi_devices)
+                # 3a. Ping-only hosts once — shared by snapshot and alert processing
+                ping_states: Dict[str, bool] = {
+                    h['name']: self.pulse.ping(h['ip'])
+                    for h in self.cfg.get('monitor', {}).get('ping_hosts', [])
+                }
+
+                # 3b. Collect and store snapshot for dashboard
+                snapshot = self._collect_snapshot(iface_states, unifi_devices, ping_states)
                 db.set_state('network_snapshot', snapshot)
                 db.set_state('last_check', _now_utc())
 
@@ -959,7 +966,7 @@ class NetworkMonitor:
                 self._process_interfaces(iface_states, suppressions)
                 self._process_unifi(unifi_devices, suppressions)
 
-                self._process_ping_hosts(suppressions)
+                self._process_ping_hosts(suppressions, ping_states)
 
                 # Housekeeping: deactivate expired suppressions and purge old resolved events
                 db.cleanup_expired_suppressions()