fix(workspace): stop the console remounting, and the idle polling re-renders

The Workspace page rendered `ConsoleArea` from two sites, picked by
`currentLane`. Every flip of that value unmounted the whole console
subtree and mounted it again at the other site: the terminal died, the
run history went with it, and `LaneConsolePane`'s lane-switch effect
wiped a half-typed prompt. It flipped on every page load (lanes arrive,
`refreshLanes` selects `lanes[0]`), on a lane being removed, and on any
refetch that re-picked the selection.

`lane-detail` is now always rendered and holds the only `ConsoleArea`;
the header and info block are the conditional parts. Same rule the
RunConsole already followed one level down — collapse with CSS, never by
unmounting — now enforced above it too.

Second half: every poller fed `setState` a brand-new object graph each
tick, re-rendering the lane strip, the card and the console area several
times a minute on a completely idle dashboard. `keepIfSame` keeps the
previous reference when the payload is value-identical, applied to the
5 s run/session poll, the lane list and counts, the `lane_update` WS
branch, and LaneCard's git/runtime/locks pollers.

Verified: npm run test:client (44 files / 454 tests), tsc --noEmit
clean, check-headers.sh clean. The Run screen snapshot was regenerated —
the diff is the added `<section>` wrapper and one indent level, no
content change.

CLAUDE.md

@@ -1,6 +1,6 @@
 # Claude Code Working Guide
 
-_Last synced: 8a812a1 (2026-09-03) + codex auto-advance._ A change that makes any statement in this file, `AGENTS.md`, or a README wrong — a moved path, a new or changed extension point, a retired rule — updates that file in the same change-set and bumps this marker.
+_Last synced: e109d28 (2026-09-04) + Workspace single console render site._ A change that makes any statement in this file, `AGENTS.md`, or a README wrong — a moved path, a new or changed extension point, a retired rule — updates that file in the same change-set and bumps this marker.
 
 ## Project mission
 - Maintain a reliable local-first dashboard for Claude Code session monitoring.
@@ -27,7 +27,7 @@ A **lane** is a durable unit of parallel agent work — one working directory, m
 - **Going back is a declaration, and it takes the nodes ahead with it.** A declaration landing on a node BEFORE the lane's current one (a fix-loop re-entry, or a new request on a lane that already reached `done`) clears the detection columns like every real transition AND drops the `stages` records of every node ahead of it — those belong to the previous pass, and left in place they render `done` with the old work's evidence beside a `current` ring further back, contradicting `progress` (computed from the declared index alone). Records under a key matching no node are left alone: unplaceable, so unprovably ahead. `ccam feature activate <slug>` is the other half of this — a feature switch archives the outgoing pipeline and clears detection too, because a detection belongs to the feature that produced it.
 - **A detection expires, an evidence rule does not.** `recordDetection` skips its forward-only comparison once `detected_at` is older than `DETECTION_TTL_MS` (default 5 min), so a lane can move backwards between work sessions. That window changes only WHICH detection is current — it never relaxes declared-wins (an agent's own claim has no expiry) and never lets an inferred node render `done`. Declared-wins has exactly ONE exception: a declaration on the pipeline's LAST node (`done`) stops vetoing, because the pipeline is over there and a later detection is new work — without it a lane left at `done` rejects every detection for the rest of its life.
 - **Working-copy facts live at `GET /api/lanes/:id/git`, never inside `GET /api/lanes`.** That endpoint shells out to git three times; the lane list is polled and re-broadcast on every hook. A cwd that is not a readable repo returns `{available:false}` with HTTP 200 — a normal state, not a fault. Cards fetch it themselves every 30s and fail silently.
-- **The Workspace console collapses with CSS, never by unmounting.** Unmounting `RunConsole` disposes the run subscription and drops a live run's rendered history.
+- **The Workspace console collapses with CSS, never by unmounting — and it has exactly ONE render site.** Unmounting `RunConsole` disposes the run subscription and drops a live run's rendered history. The same rule binds one level up: `ConsoleArea` lives inside the always-rendered `lane-detail` section in `client/src/pages/Workspace.tsx`, never inside a `{currentLane && …}` branch. A second render site makes React unmount the whole console every time `currentLane` flips — lanes arriving on mount, the selected lane removed, a refetch re-picking the selection — which kills the terminal and lets `LaneConsolePane`'s lane-switch effect wipe a half-typed prompt. Header and info block are the conditional parts; the console is not.
 - **CCAM does not orchestrate:** no chaining, no queue, no retry logic, no gate evaluation. The session in control makes all decisions; the dashboard records the claimed stage and shows evidence. The runtime layer (`ccam lanes up|down|hook`) does not change this — it offers *primitives* a session calls; nothing in the dashboard sequences them.
 - **The runtime never writes `stage`, `status` or `notes`** — only `slot` and `ports`. `status=running` means an AGENT is working, not that a server is listening; merging the two would corrupt `classifyLiveness`. Boot failures live in `LANES_ROOT/.state/lane<slot>/last-error.json` and surface via `GET /api/lanes/:id/runtime`. Same boundary as the console-never-writes-stage rule above.
 - **A lane's stack is up or down as a computed fact, never a stored one.** `runtimeFacts` re-derives it from pid files and port probes on every read. A process dies to OOM, a stray `kill`, a reboot — caching a truth CCAM does not control buys ghost state. Slot allocation is the opposite (fully controlled, must be race-free), so that one does live in the DB, under `withLaneLock` plus a partial unique index.