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/0013_appointment_confirmation.sql

@@ -0,0 +1,7 @@
+ALTER TABLE appointments
+  ADD COLUMN confirmation_status TEXT NOT NULL DEFAULT 'pending',
+  ADD COLUMN confirmed_at TIMESTAMPTZ,
+  ADD COLUMN cancelled_at TIMESTAMPTZ,
+  ADD COLUMN confirmation_token TEXT UNIQUE;
+
+CREATE INDEX idx_appointments_confirmation_token ON appointments (confirmation_token) WHERE confirmation_token IS NOT NULL;