Revert #31: open link-down alerts from a monitor glitch were revived and ticketed

#31 treated any open interface_down alert as previously up. Production had
six such alerts all created in the same second on 2026-03-02 (a monitor
glitch, on ports that were never in use: large1 enp36s0 and a USB adapter,
compute-storage-01 nic1-3, micro1 enp3s0). Reviving them opened per-host
tickets and a P1 cluster-wide ticket. Back to the previous behaviour while a
safer fix is worked out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

monitor.py

@@ -1195,10 +1195,6 @@ class NetworkMonitor:
     def _process_interfaces(self, states: Dict[str, Dict[str, bool]], suppressions: list) -> None:
         baseline = db.get_baseline()
         new_baseline = {k: dict(v) for k, v in baseline.items()}
-        # An interface with an open link-down alert was up before it went down, whatever the
-        # baseline says now: after a baseline reset it reads as "first seen down", which would
-        # leave the alert open forever without updating, ticketing or resolving it.
-        open_down = set(db.get_open_event_targets('interface_down'))
         # Only count hosts with genuine regressions (UP→DOWN) toward cluster threshold
         hosts_with_regression: List[str] = []
 
@@ -1211,8 +1207,6 @@ class NetworkMonitor:
 
             for iface, is_up in ifaces.items():
                 prev = baseline.get(host, {}).get(iface)  # 'up', 'initial_down', or None
-                if (host, iface) in open_down:
-                    prev = 'up'
 
                 if is_up:
                     new_baseline[host][iface] = 'up'