bugfix: unit status updating based on last heard, not just using cached status

backend/services/snapshot.py

@@ -24,13 +24,47 @@ def format_age(last_seen):
     return f"{int(hours)}h {int(mins)}m"
 
 
+def calculate_status(last_seen, status_ok_threshold=12, status_pending_threshold=24):
+    """
+    Calculate status based on how long ago the unit was last seen.
+
+    Args:
+        last_seen: datetime of last seen (UTC)
+        status_ok_threshold: hours before status becomes Pending (default 12)
+        status_pending_threshold: hours before status becomes Missing (default 24)
+
+    Returns:
+        "OK", "Pending", or "Missing"
+    """
+    if not last_seen:
+        return "Missing"
+
+    last_seen = ensure_utc(last_seen)
+    now = datetime.now(timezone.utc)
+    hours_ago = (now - last_seen).total_seconds() / 3600
+
+    if hours_ago > status_pending_threshold:
+        return "Missing"
+    elif hours_ago > status_ok_threshold:
+        return "Pending"
+    else:
+        return "OK"
+
+
 def emit_status_snapshot():
     """
     Merge roster (what we *intend*) with emitter data (what is *actually happening*).
+    Status is recalculated based on current time to ensure accuracy.
     """
 
     db = get_db_session()
     try:
+        # Get user preferences for status thresholds
+        from backend.models import UserPreferences
+        prefs = db.query(UserPreferences).filter_by(id=1).first()
+        status_ok_threshold = prefs.status_ok_threshold_hours if prefs else 12
+        status_pending_threshold = prefs.status_pending_threshold_hours if prefs else 24
+
         roster = {r.id: r for r in db.query(RosterUnit).all()}
         emitters = {e.id: e for e in db.query(Emitter).all()}
         ignored = {i.id for i in db.query(IgnoredUnit).all()}
@@ -48,8 +82,9 @@ def emit_status_snapshot():
                 fname = ""
             else:
                 if e:
-                    status = e.status
                     last_seen = ensure_utc(e.last_seen)
+                    # RECALCULATE status based on current time, not stored value
+                    status = calculate_status(last_seen, status_ok_threshold, status_pending_threshold)
                     age = format_age(last_seen)
                     fname = e.last_file
                 else:
@@ -86,9 +121,11 @@ def emit_status_snapshot():
         for unit_id, e in emitters.items():
             if unit_id not in roster:
                 last_seen = ensure_utc(e.last_seen)
+                # RECALCULATE status for unknown units too
+                status = calculate_status(last_seen, status_ok_threshold, status_pending_threshold)
                 units[unit_id] = {
                     "id": unit_id,
-                    "status": e.status,
+                    "status": status,
                     "age": format_age(last_seen),
                     "last": last_seen.isoformat(),
                     "fname": e.last_file,