fix(api): import isNull from @groombook/db instead of drizzle-orm directly

drizzle-orm is not a direct dependency of @groombook/api, causing
TS2307 at typecheck time. Re-export isNull from @groombook/db and
update the import in rbac.ts.

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

apps/api/src/middleware/rbac.ts

@@ -1,6 +1,5 @@
 import type { MiddlewareHandler } from "hono";
-import { isNull } from "drizzle-orm";
-import { and, eq, getDb, staff } from "@groombook/db";
+import { and, eq, getDb, isNull, staff } from "@groombook/db";
 
 export type StaffRole = "groomer" | "receptionist" | "manager";
 export type StaffRow = typeof staff.$inferSelect;

packages/db/src/index.ts

@@ -4,7 +4,7 @@ import * as schema from "./schema.js";
 
 export * from "./schema.js";
 export { encryptSecret, decryptSecret } from "./crypto.js";
-export { and, asc, desc, eq, exists, gte, gt, ilike, inArray, lt, lte, ne, or, sql } from "drizzle-orm";
+export { and, asc, desc, eq, exists, gte, gt, ilike, inArray, isNull, lt, lte, ne, or, sql } from "drizzle-orm";
 
 let _db: ReturnType<typeof drizzle> | null = null;