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/0029_db_indexes_constraints.sql

@@ -0,0 +1,20 @@
+-- Migration: 0029_db_indexes_constraints.sql
+-- Add missing indexes on appointments, pets, clients tables and NOT NULL constraint on clients.email
+
+-- Backfill NULL emails before setting NOT NULL
+UPDATE clients SET email = concat('unknown-', id::text, '@placeholder.local') WHERE email IS NULL;
+
+-- Add indexes on appointments table
+CREATE INDEX idx_appointments_client_id ON appointments(client_id);
+CREATE INDEX idx_appointments_staff_id ON appointments(staff_id);
+CREATE INDEX idx_appointments_start_time ON appointments(start_time);
+CREATE INDEX idx_appointments_status ON appointments(status);
+
+-- Add index on pets table
+CREATE INDEX idx_pets_client_id ON pets(client_id);
+
+-- Add index on clients table
+CREATE INDEX idx_clients_email ON clients(email);
+
+-- Set NOT NULL on clients.email (after backfill)
+ALTER TABLE clients ALTER COLUMN email SET NOT NULL;