fix: align compaction cuts and native usage accounting

app/api/activity/route.ts

@@ -1,8 +1,8 @@
 /**
  * GET /api/activity — the dock's one poll: every running background
  * process, every view (chat, home, everywhere). Composition only — the
- * feed lives in server/observability.ts; cost folds client-side via
- * core/prices.ts. See that module's header for why /api/jobs stays
+ * feed lives in server/observability.ts; costs are projected server-side
+ * through Pi's catalog and public calculator. See that module's header for why /api/jobs stays
  * chat-scoped and untouched.
  */
 import { activityFeed } from "@/src/server";