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/0014_customer_notes.sql

@@ -0,0 +1,3 @@
+ALTER TABLE appointments ADD COLUMN customer_notes TEXT;
+
+CREATE INDEX idx_appointments_customer_notes ON appointments (client_id) WHERE customer_notes IS NOT NULL;