Builds the dashboard UI on the /api/stats-hive endpoint: a new ST4TS
tab showing swarm totals (active agents, turns, tokens, labelled est
cost), a busiest-first per-agent table, and a model-mix bar list.
Plain tables/CSS bars — no chart lib in the dashboard bundle; per-agent
trend charts stay on each agent's own /stats page. Fetched on tab
activation + window change (pull-only, no SSE).
Also adds conn.busy_timeout(500ms) in hive_stats read_agent per review:
turn_stats is rollback-journal, so a read landing mid-INSERT would hit
SQLITE_BUSY and silently drop that active agent — wait the write out.
8e74dda4c5