docs: turn_stats sink + event-driven agent badges + dashboard event vocabulary

docs/persistence.md

@@ -41,17 +41,36 @@ One table:
   harness emits during turn loop execution.
 
 The harness writes; the host vacuums. `hive-c0re::events_vacuum`
-runs hourly and sweeps every existing agent state dir, applying the
-same two-stage delete to each file: drop rows older than 7 days,
-then trim to the 2000 most-recent. Centralising retention on the
-host means a misbehaving harness can't disable its own vacuum and
-agents don't need any cleanup wiring of their own.
+runs hourly and sweeps every existing agent state dir, deleting
+rows older than 7 days. Age-only — no row cap — so a chatty turn
+doesn't lose history sooner than a quiet one; disk pressure on a
+sustained burst is the cheaper problem to have. Centralising
+retention on the host means a misbehaving harness can't disable
+its own vacuum and agents don't need any cleanup wiring of their
+own.
 
 Path overridable via `HYPERHIVE_EVENTS_DB` (for dev / no-`/state`
 setups). On open failure the `Bus` falls back to no-store mode
 rather than crashing the harness — events still broadcast over SSE,
 just nothing persisted.
 
+### `/state/hyperhive-turn-stats.sqlite` (per agent)
+
+Per-turn analytics sink. One row per claude turn captures
+identity (`model`, `wake_from`, `result_kind`), timing
+(`started_at`, `ended_at`, `duration_ms`), cost (input / output /
+cache_read / cache_creation token counts), behaviour
+(`tool_call_count` + `tool_call_breakdown_json`), and post-turn
+snapshot metrics (`open_threads_count`,
+`open_reminders_count` — fetched via the same socket the harness
+already uses for `GetOpenThreads` + `CountPendingReminders`).
+Bin-loop helpers `build_row` + `record` land each row at
+`turn_end`; writes are best-effort, a sqlite hiccup logs + lets
+the turn loop continue.
+
+No host-side vacuum yet — tracked in `TODO.md` under Telemetry
+(target retention ~90 days, age-only sweep like events_vacuum).
+
 ### `/state/hyperhive-model` (per agent)
 
 Single-line text file holding the claude model name currently
@@ -68,8 +87,10 @@ Under `/var/lib/hyperhive/agents/<name>/`:
 - `config/` — the proposed nix repo (manager-editable).
 - `claude/` — claude OAuth credentials, bind-mounted RW to
   `/root/.claude` inside the container.
-- `state/` — durable notes + the events.sqlite db, bind-mounted
-  to `/state` inside the container.
+- `state/` — durable notes, the events.sqlite db, and the
+  turn-stats sqlite db. Bind-mounted to `/agents/<name>/state`
+  inside the container (the manager still uses the legacy
+  `/state` mount point — same host path either way).
 
 Under `/var/lib/hyperhive/applied/<name>/` — the hive-c0re-only
 applied repo. Tracks `flake.nix` (module-only boilerplate; never