Extract groombook/api from monorepo with CI workflow

- Add source code from apps/api
- Add packages/db and packages/types workspace dependencies
- Add GitHub Actions CI workflow (lint, typecheck, test, docker)
- Generate pnpm-lock.yaml
- Add .gitignore

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

packages/db/migrations/0020_typical_daimon_hellstrom.sql

@@ -0,0 +1,7 @@
+-- Clean up existing duplicate services before adding unique constraint.
+-- Keep the row with the lowest id per name; delete all others.
+DELETE FROM services WHERE id NOT IN (
+  SELECT (MIN(id::text))::uuid FROM services GROUP BY name
+);
+
+ALTER TABLE "services" ADD CONSTRAINT "services_name_unique" UNIQUE("name");