refactor: inline packages/db and packages/types into api package

Phase 2 extraction: groombook/api from groombook/app monorepo.

Changes:
- Move packages/db content to apps/api/src/db/
- Move packages/types content to apps/api/src/types/
- Inline database schema and migrations into api package
- Update Dockerfile to build single package
- Update CI workflow for single-package structure
- Fix vitest.config.ts aliases

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/routes/impersonation.ts

@@ -9,7 +9,7 @@ import {
   impersonationAuditLogs,
   clients,
   desc,
-} from "./packages/db";
+} from "../db";
 import type { AppEnv } from "../middleware/rbac.js";
 
 export const impersonationRouter = new Hono<AppEnv>();