refactor(store): consolidate the SQLite store family into bot_bottle.store

Move the DbStore base (db_store), the shared schema-migration base (migrations /
TableMigrations), the concrete stores (audit_store, config_store, queue_store),
and StoreManager out of the package root into a bot_bottle/store/ package, so
persistence lives in one place rather than scattered across the root.

Callers use direct submodule imports (from bot_bottle.store.store_manager
import StoreManager). Inside the moved modules the relative imports point back
up to their non-store siblings (..paths, ..supervise_types) while co-moved
siblings stay package-local; the flat-import fallbacks are untouched. The
orchestrator's own stores (config_store, secret_store, registry) stay in
orchestrator/ and repoint to the moved DbStore / TableMigrations.

No behavior change; full unit suite green.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

bot_bottle/orchestrator/registry.py

@@ -36,8 +36,8 @@ from collections.abc import Iterable
 from dataclasses import dataclass
 from pathlib import Path
 
-from ..db_store import DbStore
-from ..migrations import TableMigrations
+from ..store.db_store import DbStore
+from ..store.migrations import TableMigrations
 from ..paths import host_db_path
 
 # 256 bits of urandom, URL-safe — unguessable per-bottle identity token.