feat(v2): wire worker role lifecycle

backend/src/backup_tool/cli.py

@@ -7,13 +7,14 @@ import asyncio
 from collections.abc import Callable, Sequence
 from pathlib import Path
 
-from alembic import command
 from alembic.config import Config
 
+from alembic import command
 from backup_tool import __version__
 from backup_tool.config import Settings
 
 from .db.engine import assert_schema_current, create_engine
+from .worker import run_worker
 
 RoleHandler = Callable[[Settings], int]
 DATABASE_ROLES = ("web", "scheduler", "worker", "admin")
@@ -23,7 +24,12 @@ def _placeholder_role(_settings: Settings) -> int:
     return 0
 
 
-ROLE_HANDLERS: dict[str, RoleHandler] = {role: _placeholder_role for role in DATABASE_ROLES}
+ROLE_HANDLERS: dict[str, RoleHandler] = {
+    "web": _placeholder_role,
+    "scheduler": _placeholder_role,
+    "worker": run_worker,
+    "admin": _placeholder_role,
+}
 
 
 def build_parser() -> argparse.ArgumentParser: