feat(commands): drop tracker counts from /status

trackers_active / trackers_total are per-provider aggregates — once the
rest of /status is scoped to the chat's album set (total_albums and
last_event both filtered by the derived scope), leaving tracker counts
in would leak info about trackers this chat has no visibility into.

- _cmd_status no longer emits trackers_active / trackers_total.
- Immich default status templates (en, ru) just show Albums + Last event.
- Variable catalog updated so the template editor stops suggesting the
  removed vars for the Immich /status slot.

packages/server/src/notify_bridge_server/api/command_template_configs.py

@@ -138,13 +138,11 @@ async def get_command_variables(
     # --- Immich-specific ---
     immich = {
         "status": {
-            "description": "/status tracker summary",
+            "description": "/status tracker summary (scoped to this chat)",
             "variables": {
                 **common_vars,
-                "trackers_active": "Number of active trackers",
-                "trackers_total": "Total tracker count",
-                "total_albums": "Total tracked albums",
-                "last_event": "Last event timestamp string",
+                "total_albums": "Tracked albums visible to this chat",
+                "last_event": "Last event timestamp string (scoped to this chat's albums)",
             },
         },
         "albums": {