refactor: inline TableMigrations into store constructors

Move _MIGRATIONS from module scope into AuditStore.__init__ and
QueueStore.__init__, treating table schema as a hidden implementation
detail of each store class.

bot_bottle/audit_store.py

@@ -15,10 +15,14 @@ except ImportError:
     from migrations import TableMigrations  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
 
 
-# One entry per schema version: _MIGRATIONS.migrations[0] brings a fresh DB
-# to version 1, [1] to version 2, and so on.  Add new migrations at the end;
-# never edit existing ones.
-_MIGRATIONS = TableMigrations("audit_store", [
+class AuditStore(DbStore):
+    """SQLite-backed persistent store for supervise audit entries."""
+
+    def __init__(self, db_path: Path | None = None) -> None:
+        # One entry per schema version: migrations[0] brings a fresh DB to
+        # version 1, [1] to version 2, etc.  Add new entries at the end; never
+        # edit existing ones.
+        migrations = TableMigrations("audit_store", [
             # v1 — initial schema
             """
             CREATE TABLE IF NOT EXISTS supervise_audit_entries (
@@ -32,14 +36,8 @@ _MIGRATIONS = TableMigrations("audit_store", [
                 diff TEXT NOT NULL
             )
             """,
-])
-
-
-class AuditStore(DbStore):
-    """SQLite-backed persistent store for supervise audit entries."""
-
-    def __init__(self, db_path: Path | None = None) -> None:
-        super().__init__(db_path or host_db_path(), _MIGRATIONS)
+        ])
+        super().__init__(db_path or host_db_path(), migrations)
 
     def write_audit_entry(self, entry: AuditEntry) -> Path:
         with self._connect() as conn:

bot_bottle/queue_store.py

@@ -16,10 +16,23 @@ except ImportError:
     from migrations import TableMigrations  # type: ignore[import-not-found]  # pylint: disable=import-error,no-name-in-module
 
 
-# One entry per schema version: _MIGRATIONS.migrations[0] brings a fresh DB
-# to version 1, [1] to version 2, and so on.  Add new migrations at the end;
-# never edit existing ones.
-_MIGRATIONS = TableMigrations("queue_store", [
+class QueueStore(DbStore):
+    """SQLite-backed persistent store for supervise proposals and responses."""
+
+    def __init__(self, queue_key: str, db_path: Path | None = None) -> None:
+        self.queue_key = queue_key
+        if db_path is not None:
+            resolved = db_path
+        else:
+            # In the sidecar container SUPERVISE_DB_PATH points at the
+            # bind-mounted host DB. On the host this env var is never set,
+            # so we always fall through to host_db_path().
+            env_path = os.environ.get("SUPERVISE_DB_PATH", "").strip()
+            resolved = Path(env_path) if env_path else host_db_path()
+        # One entry per schema version: migrations[0] brings a fresh DB to
+        # version 1, [1] to version 2, etc.  Add new entries at the end; never
+        # edit existing ones.
+        migrations = TableMigrations("queue_store", [
             # v1 — proposals table
             """
             CREATE TABLE IF NOT EXISTS supervise_proposals (
@@ -47,23 +60,8 @@ _MIGRATIONS = TableMigrations("queue_store", [
                 PRIMARY KEY (queue_key, proposal_id)
             )
             """,
-])
-
-
-class QueueStore(DbStore):
-    """SQLite-backed persistent store for supervise proposals and responses."""
-
-    def __init__(self, queue_key: str, db_path: Path | None = None) -> None:
-        self.queue_key = queue_key
-        if db_path is not None:
-            resolved = db_path
-        else:
-            # In the sidecar container SUPERVISE_DB_PATH points at the
-            # bind-mounted host DB. On the host this env var is never set,
-            # so we always fall through to host_db_path().
-            env_path = os.environ.get("SUPERVISE_DB_PATH", "").strip()
-            resolved = Path(env_path) if env_path else host_db_path()
-        super().__init__(resolved, _MIGRATIONS)
+        ])
+        super().__init__(resolved, migrations)
 
     def write_proposal(self, proposal: Proposal) -> Path:
         with self._connect() as conn: