fix(web): show the whole last turn in the Claude response viewer's brief view

The eye button rendered `data.text`, which is one row: the last assistant
row of the transcript. A Claude answer is a median of 3 model messages
(p90 11) split around tool calls, so the brief view usually showed the tail
of an answer ("Done.", "Let me look.") and the substance appeared only after
More. The full view was fine, which is why the brief one read as broken by
comparison.

The brief view now asks `?context=turn`. The reader answers with the
assistant messages of the last ANSWERED turn (`selectLastAnsweredTurn`: the
highest `turn` that has an assistant row, so a prompt queued after the
answer does not blank the view) and the frontend renders them exactly as
the full view renders that turn: one badge, then continuation segments,
gated on the numeric `turn` as before.

`data.text` is unchanged in every context — still the last assistant row,
never `messages.at(-1)` — because agent pollers hash it. Readers that emit
no turns (Codex, the pane parser, DeepSeek, an older server) return `text`
only for `context=turn`, and the brief view keeps its single card for them.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01McLWqCWBuQYGuPMScb4Aou

docs/architecture-invariants.md

@@ -361,7 +361,7 @@ Anatomy: `.set-shell` → `.set-shell-head` (title + `.set-head-actions`) + `.se
 
 ⚠️ **`Session.lastSubmitAt` is persisted state, not a runtime counter.** `start()` reassigns `_claudeSessionId = resumeSessionId || id` on every launch — including the re-attach path for a mux session that survived the restart — so a recovered pane always points the viewer at its *launch* conversation, even when the CLI moved on via `/clear` hours earlier. The submit anchor is the only thing that can correct that without user input, so it round-trips through `SessionState.lastSubmitAt` and is restored in `restoreMuxSessions()`. Drop it from `toState()` and recovered panes silently show the pre-`/clear` transcript until the user types again. Restoring a *stale* anchor is safe: the resolver's staleness guard rejects any candidate transcript older than the one the pane is currently on, which is exactly the shape of a respawn into a fresh conversation.
 
-⚠️ **The Claude viewer emits one message per model message and groups them with `turn`; it never concatenates them.** A Claude transcript is an append-only event log, so one logical exchange spans many rows: tool-result rows, meta/image/skill rows, compact summaries, task/team notifications, sidechains, replayed assistant snapshots. Rendering a card per *row* was the original bug (#169) — but the fix overshot to one card per *human turn*, which fused up to 74 distinct model messages into a single card and reported it as one message. One assistant row IS one whole model message: measured across a real `~/.claude/projects` (CLI 2.1.220-2.1.251) no assistant row carries more than one content block and no `message.id` carries more than one text block, so there was never anything to reassemble, and no adjacent pair of assistant rows continues a table, a list, or an open code fence. Each row is therefore its own message carrying `{kind, label, role, text, timestamp, turn}`; the frontend renders a same-role run inside one `turn` as badge-less continuation segments (`.rv-msg-cont`), which is what keeps a p90 of 11 messages per turn from reading as card spam. ⚠️ **A prompt typed while Claude is working is recorded ONLY as an `attachment/queued_command` row** — the CLI never re-emits it as a `user` row — so reading only `user` rows lost 162 of 353 user cards on that corpus AND lost the turn boundary each one carries, which is what let an assistant run fuse in the first place. Take it only when `attachment.origin.kind === 'human'` and `commandMode === 'prompt'`; the CLI's own queue entries (`commandMode: 'task-notification'`) carry no `origin` key at all. The shape is not a documented CLI contract, so every field check must fail closed. ⚠️ **`data.text` (no `?context=full`) is frozen on the last assistant row and must never be derived from `messages.at(-1)`** — agent pollers hash it (`skills/codeman/preamble.sh`), and the last message can be the user's own queued prompt. Replayed assistant snapshots are still deduped, and the tool/task/skill/compact/team metadata filtering is unchanged. Related: a recovered `restored-<uuid8>` tmux placeholder carries a **stale cwd**, so transcript lookup by working directory finds nothing; it rebinds to the matching top-level Claude transcript UUID instead when that match is unambiguous. Tests: `test/routes/session-routes-claude-last-response.test.ts`, `test/response-viewer-turn-segments.test.ts`. Purely client-side (no `renderIndexHtml` step): the template ships with `btn-response-viewer-header--hidden` and `applyHeaderVisibilitySettings()` (settings-ui.js) toggles it after settings load. Hiding must go through that marker class — the base rule is `display:inline-flex !important`, so an inline style can't override it. `showResponseViewer` is in the `displayKeys` per-device set (settings-ui.js), so it does NOT sync across devices.
+⚠️ **The Claude viewer emits one message per model message and groups them with `turn`; it never concatenates them.** A Claude transcript is an append-only event log, so one logical exchange spans many rows: tool-result rows, meta/image/skill rows, compact summaries, task/team notifications, sidechains, replayed assistant snapshots. Rendering a card per *row* was the original bug (#169) — but the fix overshot to one card per *human turn*, which fused up to 74 distinct model messages into a single card and reported it as one message. One assistant row IS one whole model message: measured across a real `~/.claude/projects` (CLI 2.1.220-2.1.251) no assistant row carries more than one content block and no `message.id` carries more than one text block, so there was never anything to reassemble, and no adjacent pair of assistant rows continues a table, a list, or an open code fence. Each row is therefore its own message carrying `{kind, label, role, text, timestamp, turn}`; the frontend renders a same-role run inside one `turn` as badge-less continuation segments (`.rv-msg-cont`), which is what keeps a p90 of 11 messages per turn from reading as card spam. ⚠️ **A prompt typed while Claude is working is recorded ONLY as an `attachment/queued_command` row** — the CLI never re-emits it as a `user` row — so reading only `user` rows lost 162 of 353 user cards on that corpus AND lost the turn boundary each one carries, which is what let an assistant run fuse in the first place. Take it only when `attachment.origin.kind === 'human'` and `commandMode === 'prompt'`; the CLI's own queue entries (`commandMode: 'task-notification'`) carry no `origin` key at all. The shape is not a documented CLI contract, so every field check must fail closed. ⚠️ **`data.text` (no `?context=full`) is frozen on the last assistant row and must never be derived from `messages.at(-1)`** — agent pollers hash it (`skills/codeman/preamble.sh`), and the last message can be the user's own queued prompt. The BRIEF view therefore does not render `text`: it asks for `?context=turn`, which returns the assistant messages of the last ANSWERED turn (`selectLastAnsweredTurn()` in `src/web/response-viewer-transcript.ts`: the highest `turn` that has an assistant row, so a prompt queued after the answer does not blank the view), and renders them with the same numeric-`turn` continuation gate as the full view. `text` alone was the final row of a median-3-row turn — a "Done." tail with the substance in the rows before it. Readers that emit no `turn` (Codex, the pane parser, an older server) return `text` only, and the brief view falls back to one card for them. Replayed assistant snapshots are still deduped, and the tool/task/skill/compact/team metadata filtering is unchanged. Related: a recovered `restored-<uuid8>` tmux placeholder carries a **stale cwd**, so transcript lookup by working directory finds nothing; it rebinds to the matching top-level Claude transcript UUID instead when that match is unambiguous. Tests: `test/routes/session-routes-claude-last-response.test.ts`, `test/response-viewer-turn-segments.test.ts`. Purely client-side (no `renderIndexHtml` step): the template ships with `btn-response-viewer-header--hidden` and `applyHeaderVisibilitySettings()` (settings-ui.js) toggles it after settings load. Hiding must go through that marker class — the base rule is `display:inline-flex !important`, so an inline style can't override it. `showResponseViewer` is in the `displayKeys` per-device set (settings-ui.js), so it does NOT sync across devices.
 **File Viewer button** (header, 1.4.1) is **shown by default on desktop** since `211f3c0` (post-1.8.0): toggle under App Settings → Header & Panels → Header buttons → File Viewer (`showFileViewerButton`, in the per-device `displayKeys` set, fallback default `true`). Purely client-side like the response viewer: the template now ships the button VISIBLE (no `--hidden` class) and `applyHeaderVisibilitySettings()` toggles the `btn-file-viewer--hidden` marker class after settings load; phones still hide it via mobile.css. The button toggles the file-browser panel open/closed without opening the settings modal (`panels-ui.js`). The same commit set the **default desktop header** to WS/CPU/MEM + File Viewer + gear: the token-count chip (`showTokenCount`, no settings-UI toggle) and the lifecycle-log button (`showLifecycleLog`) both default **OFF** now (templates ship them hidden; stored prefs still honored). The plan-usage chip default is unchanged (opt-in, see Plan-usage chip). The **Cron toolbar button** joined the same opt-in pattern in 1.6.0: template ships `btn-cron--hidden`, `applyHeaderVisibilitySettings()` toggles it via the per-device `showCronButton` setting (default OFF, App Settings → Header & Panels → Scheduling); cron jobs themselves are unaffected.
 
 ### Session list layout (header strip vs. left sidebar)