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/0011_impersonation_indexes.sql

@@ -0,0 +1,6 @@
+-- Add indexes on impersonation tables to prevent full table scans
+-- Ref: GitHub #95
+
+CREATE INDEX "impersonation_sessions_staff_id_status_idx" ON "impersonation_sessions" USING btree ("staff_id","status");--> statement-breakpoint
+CREATE INDEX "impersonation_sessions_client_id_idx" ON "impersonation_sessions" USING btree ("client_id");--> statement-breakpoint
+CREATE INDEX "impersonation_audit_logs_session_id_idx" ON "impersonation_audit_logs" USING btree ("session_id");