feat: assert user is member of workspace for board routes

packages/api/src/utils/auth.ts

@@ -0,0 +1,22 @@
+import { TRPCError } from "@trpc/server";
+
+import type { dbClient } from "@kan/db/client";
+import * as workspaceRepo from "@kan/db/repository/workspace.repo";
+
+export async function assertUserInWorkspace(
+  db: dbClient,
+  userId: string,
+  workspaceId: number,
+) {
+  const isMember = await workspaceRepo.isUserInWorkspace(
+    db,
+    userId,
+    workspaceId,
+  );
+
+  if (!isMember)
+    throw new TRPCError({
+      message: `You do not have access to this workspace`,
+      code: "FORBIDDEN",
+    });
+}