docs sync + revert auto-unfree removal

revert the earlier 'operator must set allowUnfree' move:
per-agent containers evaluate their own nixpkgs and the operator's
host-level allowUnfree doesn't propagate in. restoring the scoped
allowUnfreePredicate inside both the claude-unstable overlay and
harness-base.nix; documented in README + gotchas as 'nothing to
set on the operator side'.

docs:
- claude.md file map adds crash_watch.rs, kick_agent on coordinator,
  /api/model + journald viewer + bind-with-retry references.
- scratchpad rewritten to reflect the recent run.
- web-ui.md: notification row + browser notifications section,
  state row (badge + model chip + last-turn chip + cancel button),
  per-agent inbox, /model slash, /cancel-question + journald
  endpoints, focus-preservation on refresh.
- turn-loop.md: --model is read from Bus::model() per turn (runtime
  override via /model); recv(wait_seconds) up to 180s with the
  rationale; ask_operator gains ttl_seconds; new TurnState section;
  kick_agent inbox-on-startup hint.
- approvals.md: ttl/cancel resolution paths for operator questions.
- persistence.md: /state/hyperhive-model file.
- gotchas.md: web UI port collision policy (rename, don't probe);
  bind retry + SO_REUSEADDR shape; auto-unfree restored.
- todo.md: cleaned up empty sections and stale entries; /model
  shipped, dropped from the list.

docs/web-ui.md

@@ -20,46 +20,84 @@ listener: read `data-confirm`, swap the button to a spinner, POST
 `application/x-www-form-urlencoded`, re-enable the button on success
 (refreshState may keep the form mounted, so we don't rely on a
 re-render), call `refreshState()`. State shapes live in
-`dashboard.rs::StateSnapshot` and `web_ui.rs::StateSnapshot` —
-when adding state fields, plumb through the snapshot struct and the
+`dashboard.rs::StateSnapshot` and `web_ui.rs::StateSnapshot` — when
+adding state fields, plumb through the snapshot struct and the
 relevant `assets/app.js` render function.
 
+**Focus preservation:** `refreshState` checks whether
+`document.activeElement` sits inside one of the managed sections
+and, if so, skips the refresh (defers 2s). The operator never has
+the form yanked out from under them mid-type; the update lands as
+soon as they blur.
+
+Both bind their listeners with `SO_REUSEADDR` via
+`tokio::net::TcpSocket` plus a retry loop on `AddrInUse` (12 tries,
+exponential backoff capped at 2s) so an nspawn restart that races
+the previous process's socket release resolves itself.
+
 ## Dashboard sections (top to bottom)
 
-1. **C0NTAINERS** — live containers with their action surface.
-2. **K3PT ST4T3** — destroyed-but-state-kept tombstones (size +
+1. **Notification row** — `🔔 enable notifications` button when
+   permission ungranted; `🔕 mute / 🔔 unmute` toggle once granted;
+   inline "unsupported / blocked" message when applicable. Sits
+   under the banner.
+2. **C0NTAINERS** — live containers with their action surface.
+3. **K3PT ST4T3** — destroyed-but-state-kept tombstones (size +
    age + claude-creds badge). Two actions: `⊕ R3V1V3` (queues a
    Spawn approval; existing state is reused), `PURG3` (wipes
    state + applied dirs; `POST /purge-tombstone/{name}`).
-3. **M1ND H4S QU3STI0NS** — pending `ask_operator` questions
-   (amber pulsing border). Always renders a free-text fallback
+4. **M1ND H4S QU3STI0NS** — pending `ask_operator` questions
+   (amber pulsing border). Free-text fallback always rendered
    alongside any option list; `multi=true` renders options as
    checkboxes; submit merges selections + free text comma-joined.
-4. **0PER4T0R 1NB0X** — recent messages addressed to `operator`
+   Each row has a `✗ CANC3L` button that resolves the question
+   with `[cancelled]`. Questions with a `ttl_seconds` show a
+   `⏳ MM:SS` chip; the host-side watchdog auto-cancels with
+   `[expired]` when the deadline fires.
+5. **0PER4T0R 1NB0X** — recent messages addressed to `operator`
    (last 50, from the broker).
-5. **P3NDING APPR0VALS** — the queue. The R3QU3ST SP4WN form
-   lives at the top of this section since submitting it immediately
-   queues an approval that lands directly below.
-6. **MESS4GE FL0W** — live broker SSE tail.
+6. **P3NDING APPR0VALS** — the queue. The R3QU3ST SP4WN form
+   lives at the top of this section since submitting it
+   immediately queues an approval that lands directly below.
+7. **MESS4GE FL0W** — live broker SSE tail.
 
 ### Container row
 
 Two-line layout (`assets/app.js::renderContainers`):
 
 - Line 1: agent name (link → new tab), m1nd/ag3nt chip, `needs
-  login` / `needs update` warning badges, in-flight `◐ pending-state…`
-  pill (replaces buttons during start/stop/restart/rebuild/destroy),
-  container name + port.
+  login` / `needs update` warning badges, in-flight `◐
+  pending-state…` pill (replaces buttons during start / stop /
+  restart / rebuild / destroy), container name + port.
 - Line 2: action buttons — `↻ R3BU1LD` always, `DESTR0Y` + `PURG3`
   on sub-agents, `↺ R3ST4RT` + (sub-agents) `■ ST0P` when running,
   `▶ ST4RT` when stopped. Buttons dim + disable while a transient
   lifecycle action is in flight.
+- Plus a collapsible `↳ logs · <container>` `<details>` block.
+  Expanding lazy-fetches journald output via `GET
+  /api/journal/{name}?unit=...&lines=...` (`journalctl -M
+  <container> -b --no-pager --output=short-iso`). A unit dropdown
+  switches between the harness service (default) and the full
+  machine journal; refresh button re-fetches.
 
 `↻ UPD4TE 4LL` button appears above the containers list when any
-agent is stale.
+agent is stale. Banner pulses on each broker SSE event
+(`pulseBanner` with a 4s grace timer).
 
-Banner pulses on each broker SSE event (`pulseBanner` with a 4 s
-grace timer).
+### Browser notifications
+
+Pure frontend (`Notification` API). Three signals trigger them:
+
+- new pending approval (per id, delta on `/api/state`)
+- new pending operator question (per id)
+- new broker message sent `to: "operator"` (live via SSE)
+
+First `/api/state` after page load seeds "seen" sets without
+firing — only items that arrive while the page is open count.
+`tag: "hyperhive"` collapses bursts; click focuses the dashboard
+tab. localStorage-backed mute toggle silences without revoking
+the OS permission. Requires a secure context (HTTPS or
+localhost); on other origins the controls hide themselves.
 
 ### Dashboard endpoints
 
@@ -67,20 +105,38 @@ grace timer).
 - `POST /{rebuild,kill,restart,start,destroy}/{name}` — lifecycle.
 - `POST /purge-tombstone/{name}` — wipe a tombstone's state dirs.
 - `POST /answer-question/{id}` — answer a pending operator question.
+- `POST /cancel-question/{id}` — cancel a pending question with
+  the sentinel `[cancelled]`. Same code path as a real answer.
 - `POST /request-spawn` — queue a Spawn approval.
 - `POST /update-all` — rebuild every stale container.
+- `GET /api/journal/{name}?unit=&lines=` — journalctl viewer for
+  a managed container.
 
 ## Per-agent page
 
 Layout, top to bottom:
 
 - Banner (gradient shimmer while state=thinking).
-- Title with `↻ R3BU1LD` button.
+- Title with `↑ DASHB04RD` back-link (new tab) + `↻ R3BU1LD`.
 - Status section (online / needs login / login-in-progress).
-- State badge row (`💤 idle / 🧠 thinking / ○ offline · <age>`) +
-  `■ cancel turn` button visible while state=thinking.
-- Terminal-wrap: live event tail (with sticky-bottom auto-scroll
-  and a `↓ N new` pill when not at bottom) followed by an
+- **State row**: state badge + model chip + last-turn timing +
+  cancel-turn button.
+  - State badge: `💤 idle` / `🧠 thinking` / `📦 compacting` /
+    `○ offline` / `… booting`, with an age suffix (`12s`,
+    `2m 14s`). Driven from `/api/state.turn_state` +
+    `turn_state_since`; SSE turn_start/turn_end still flip it
+    instantly between polls. Authoritative source is the
+    harness's `Bus::state_snapshot()`.
+  - Model chip: `model · <name>` (e.g. `model · haiku`).
+  - Last-turn chip: `last turn 12.3s` appears after the first
+    turn ends, computed from the state-since deltas.
+  - `■ cancel turn` button: visible only while state=thinking,
+    POSTs `/api/cancel`.
+- Inbox `<details>` block (collapsed): `inbox · N` — last 30
+  messages addressed to this agent, fetched via
+  `AgentRequest::Recent { limit: 30 }`.
+- Terminal-wrap: live event tail (sticky-bottom auto-scroll +
+  `↓ N new` pill when not at bottom) followed by an
   operator-input textarea acting as a prompt.
 
 ### Live view
@@ -92,25 +148,32 @@ The harness emits `TurnStart { from, body, unread }`,
 `TurnEnd { ok, note }`. The web UI:
 
 - fetches `GET /events/history` on page load and replays the last
-  2000 events (oldest first, with `.no-anim` so they don't stagger);
+  2000 events (oldest first, with `.no-anim` so they don't
+  stagger);
 - then subscribes to `GET /events/stream` (SSE) for live tail;
-- shows a granular state badge above the terminal, driven from
-  `turn_start`/`turn_end`, with a flash animation on transition;
+- shows a granular state badge above the terminal, driven
+  authoritatively from `/api/state.turn_state`. SSE turn_start /
+  turn_end still flip the badge instantly between renders;
 - sticky-bottom auto-scroll: scrolling up parks the view; new rows
   surface a "↓ N new" pill instead of yanking;
-- terminal-themed: phosphor mauve glow, Crust bg, backdrop-filter
-  blur, row fade-in slide-up.
+- terminal-themed: phosphor mauve glow, Crust bg,
+  backdrop-filter blur, row fade-in slide-up.
 
 Per-stream rendering:
 
-- `Stream` `tool_use` → `→ Read /path` / `→ Bash $ cmd` / `→ send →
-  operator: "..."` etc., per-tool pretty rather than raw JSON.
+- `Stream` `tool_use` →
+  - `Write` / `Edit`: collapsed `<details>` with a +/- diff body
+    (`-` lines from `input.old_string`, `+` lines from
+    `input.new_string` or every line of `input.content`).
+    Summary carries the path + line counts.
+  - others (`Read /path`, `Bash $ cmd`, `mcp__hyperhive__send →
+    operator: "..."`, etc.): flat one-line per-tool format.
 - `Stream` `tool_result` short → flat `← ...`; long → collapsed
   `<details>` `▸ ← Nl · headline` (click to expand full body).
 - `Stream` `thinking` → text content if claude provided one,
   otherwise the bare `· thinking …` indicator.
-- `Stream` `system init`, `result`, `rate_limit_event` are dropped
-  — too noisy.
+- `Stream` `system init`, `result`, `rate_limit_event` are
+  dropped — too noisy.
 - `Note` → `· text`.
 - `TurnEnd` → `✓ turn ok` / `✗ turn fail — note`, triggers a
   `refreshState()`.
@@ -118,19 +181,23 @@ Per-stream rendering:
 ### Terminal-embedded prompt
 
 The operator input lives *inside* the terminal-wrap as a
-prompt-style textarea below the live tail: multi-line (Enter sends,
-Shift+Enter newlines), tab-completes slash commands.
+prompt-style textarea below the live tail: multi-line (Enter
+sends, Shift+Enter newlines), tab-completes slash commands.
 
 Slash commands today:
 
-- `/help` — list commands locally
-- `/clear` — wipe the local terminal view (server history kept)
+- `/help` — list commands locally.
+- `/clear` — wipe the local terminal view (server history kept).
 - `/cancel` — `POST /api/cancel` → host shellouts `pkill -INT
-  claude`, emits a Note. Also surfaces as a `■ cancel turn` button
-  in the state row while state=thinking.
+  claude`, emits a Note. Also surfaces as a `■ cancel turn`
+  button in the state row while state=thinking.
 - `/compact` — `POST /api/compact` → host spawns
   `turn::compact_session` in the background; output streams into
   the live panel.
+- `/model <name>` — `POST /api/model` flipping `Bus::set_model`.
+  Takes effect on the next turn; persisted to
+  `/state/hyperhive-model` so the override survives harness
+  restart / rebuild.
 
 Unknown `/foo` shows an error row instead of being silently sent.
 
@@ -140,4 +207,6 @@ Unknown `/foo` shows an error row instead of being silently sent.
 - `POST /login/{start,code,cancel}` — claude OAuth login flow.
 - `POST /api/cancel` — SIGINT the in-flight claude turn.
 - `POST /api/compact` — run `/compact` on the persistent session.
+- `POST /api/model` (`model=<name>`) — switch the model for
+  future turns.
 - `GET /events/history` — replay buffer for the terminal.