fix: npm -> pnpm

frontend/openapi-ts.config.ts

@@ -1,7 +1,7 @@
 import { defineConfig } from "@hey-api/openapi-ts";
 
 // Reads the schema from the running dev server: start `make run` first, then
-// `npm run generate:api` (or `make api-client`) after changing tracker/api.py.
+// `pnpm run generate:api` (or `make api-client`) after changing tracker/api.py.
 export default defineConfig({
   input: "http://127.0.0.1:8000/api/openapi.json",
   output: "src/api",