refactor: simplify comments, styling, and conflict-resolution control flow

- replace stale plan-reference comments with intent-describing ones
- move inline nav style to a .site-nav CSS class
- drop dummy placeholder return in generate-key resolveConflict

lib/supabase/server-client.js

@@ -5,8 +5,8 @@ import { cookies } from "next/headers";
 
 /**
  * Cookie-based Supabase client (anon key) for reading/refreshing the auth
- * session on the server. Use this to know WHO the request is (Phase 3 identity),
- * never to touch `api_keys` — that table lives in the unexposed `llmapikey`
+ * session on the server. Use this to know WHO the request is, never to touch
+ * `api_keys` — that table lives in the unexposed `llmapikey`
  * schema and is reached only via the direct Postgres client (lib/db).
  *
  * In Server Components cookie writes throw; we swallow that — session refresh