chore: replace em dashes with hyphens, add no-em-dash rule to CLAUDE.md

web/app/healthz/route.ts

@@ -3,7 +3,7 @@ import { NextResponse } from "next/server";
 // Liveness and readiness for the Next server itself. Deliberately at /healthz
 // and not /api/healthz: next.config.ts rewrites the whole of /api to the Go
 // server, so a probe there would report the backend's health instead of this
-// process's — and would keep passing while this pod was wedged.
+// process's - and would keep passing while this pod was wedged.
 //
 // It answers without touching the backend on purpose. web is stateless; a
 // backend outage must not take every web replica out of its Service as well,