feat: entity relationship refactor — notification trackers, command system, chat actions

Rework entity schema: rename Tracker→NotificationTracker, add CommandConfig/
CommandTracker/CommandTrackerListener entities for decoupled command handling.
Commands now resolve through CommandTracker→CommandConfig instead of
TelegramBot.commands_config. Smart ref-counted bot polling based on active
listeners. Add chat_action to telegram targets. Full frontend CRUD pages
for command configs and command trackers. Idempotent SQLite migrations.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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

@@ -10,7 +10,7 @@ from typing import Any
 
 from ..auth.dependencies import get_current_user
 from ..database.engine import get_session
-from ..database.models import NotificationTarget, TelegramBot, TelegramChat, TrackerTarget, User
+from ..database.models import NotificationTarget, NotificationTrackerTarget, TelegramBot, TelegramChat, User
 from ..services.notifier import send_test_notification
 
 _LOGGER = logging.getLogger(__name__)
@@ -23,12 +23,14 @@ class TargetCreate(BaseModel):
     name: str
     icon: str = ""
     config: dict[str, Any] = {}
+    chat_action: str | None = None
 
 
 class TargetUpdate(BaseModel):
     name: str | None = None
     icon: str | None = None
     config: dict[str, Any] | None = None
+    chat_action: str | None = None
 
 
 @router.get("")
@@ -80,6 +82,7 @@ async def create_target(
         name=body.name,
         icon=body.icon,
         config=body.config,
+        chat_action=body.chat_action,
     )
     session.add(target)
     await session.commit()
@@ -125,7 +128,7 @@ async def delete_target(
     target = await _get_user_target(session, target_id, user.id)
     # Delete associated tracker-target links
     result = await session.exec(
-        select(TrackerTarget).where(TrackerTarget.target_id == target_id)
+        select(NotificationTrackerTarget).where(NotificationTrackerTarget.target_id == target_id)
     )
     for tt in result.all():
         await session.delete(tt)
@@ -153,6 +156,7 @@ def _target_response(target: NotificationTarget, chat_names: dict[str, str] | No
         "name": target.name,
         "icon": target.icon,
         "config": _safe_config(target),
+        "chat_action": target.chat_action,
         "created_at": target.created_at.isoformat(),
     }
     # Attach resolved chat name for telegram targets