fix(dashboard): update 'view queue' link to /builds.html
The build queue moved to its own /builds.html page. The queue-summary
'view queue →' link in tabs.js still pointed at /core.html, so clicking
it landed on the wrong page.
fix(broker): filter agent inbox to unread (acked_at IS NULL)
recent_for was returning all messages regardless of ack state, so the
agent inbox showed everything even after 'mark all read'. Now filters
to acked_at IS NULL — mirroring exactly what mark_all_read drains —
so the inbox empties on reload after the operator drains it.
5264828091