fix(git): the interval fetches one run per folder, and the rest of the review (review)

The scheduler is the part that runs with nobody watching, so it is decided per folder
rather than per session: sessions sharing a folder are the same clone and share one run
that both see, `inFlight`/`lastRunAt` are keyed by the resolved folder, the schedule is
stamped when a folder is picked instead of when its run starts, and a tick is skipped
while the previous one is still going. The click route joins a run already going for the
same folder rather than starting a second fetch in one clone.

The tick keeps ONE bound for the git processes of the whole run and hands it to every
folder, and bounds its folders with a bound of its own: the same semaphore cannot serve
both levels, because a folder holding a slot would then wait for a slot its own fetch
needs. Both bounds are `FETCH_CONCURRENCY`, so the ceiling is unchanged. The bound claim
in CLAUDE.md, the `Limiter` jsdoc and docs/api-reference.md now describes it as it is.

Before anything is fetched the folder is probed with the bounded path probe, so a case on
a mount that stopped answering is skipped and never touched.

The rest of the review: the hooks are named as they really are (`reference-transaction`,
`pre-auto-gc` through the maintenance a fetch triggers, config commands such as
`credential.helper`) and `FETCH_CONFIG_ARGS` turns maintenance and gc off for an
unattended run; the claim that an agent in the same repository is not disturbed is
replaced by the ref-lock collision it actually is; the click route publishes its own run
as `trigger: 'click'`; `autoSaveGitFetch` uses `_apiJson` so a 400 shows the error toast
and applies the returned settings; and the two wording fixes.

Tests: the scheduler pins one run per folder, the two bounds, the probe before anything
runs, and that closing the session holding the override keeps the folder while another
session is still open on it; the route test pins the click publish and the join, asserting
the join before the held run is released — releasing first lets the run finish and clears
the lane, so the joiner would be entitled to its own fetch and the test would pass for the
wrong reason.

docs/api-reference.md

@@ -1175,11 +1175,11 @@ Both routes accept two optional query parameters, which the UI sends from its pe
 
 Lists are capped (300 files and 50 commits per repository) while the counts stay exact. A branch with no upstream reports the commits no remote has (`HEAD --not --remotes`); a repository with no remote reports `unpushedCount: 0`, since there is nothing to push to. Concurrent polls of one folder share a single git invocation; `?fresh=1` (what the panel's Refresh button and opening the panel send) skips the short-lived caches, though it still joins a computation already running.
 
-`POST /api/sessions/:id/git-fetch` is the panel's **Fetch** button: one `git fetch --quiet` per repository the panel would show, through the same resolver so the two cannot disagree about which repositories belong to a workspace, with the same `maxRepos` and `timeout` clamps. It is the only git command Codeman runs that writes, and it writes remote-tracking refs only — nothing commits, checks out, merges or touches the working tree, so an agent working in the same repository is not disturbed. It runs on that click, or on the interval below and never otherwise, and `git fetch` is exactly the command that runs a repository's own `fetch-post` hook, which is why nothing runs on a timer until you opt in, and why a repository at or inside a Docker case workspace is refused before any git runs. Remote and Docker sessions answer `state: 'unsupported'` like the status route. Bounded: 4 repositories at a time, one spawn per repository with the same per-command timeout, `GIT_TERMINAL_PROMPT=0` plus BatchMode ssh so a repository that needs a login fails fast instead of hanging the request on an invisible prompt — Codeman supplies no credentials, so a repository your own git is already signed in to works because that is your existing setup.
+`POST /api/sessions/:id/git-fetch` is the panel's **Fetch** button: one `git fetch --quiet` per repository the panel would show, through the same resolver so the two cannot disagree about which repositories belong to a workspace, with the same `maxRepos` and `timeout` clamps. It is the only git command Codeman runs that writes, and it writes remote-tracking refs only — nothing commits, checks out, merges or touches the working tree. It is not quite as harmless as a read: a fetch holds git's ref lock, so an agent's own `git pull` in the same clone can hit the same `cannot lock ref` while a fetch is running, which is why one folder is fetched by one run at a time. It runs on that click, or on the interval below and never otherwise, and `git fetch` is exactly the command that can run a repository's own hooks (`reference-transaction`, `pre-auto-gc` through the automatic maintenance a fetch triggers, and config commands such as `credential.helper`), which is why nothing runs on a timer until you opt in, and why a repository at or inside a Docker case workspace is refused before any git runs. Remote and Docker sessions answer `state: 'unsupported'` like the status route. Bounded: 4 repositories at a time across the whole run (one shared bound, not one per repository group — a scheduled tick keeps that one bound for all its folders, so 4 folders do not mean 4 × 4, and works at most 4 folders at a time), one spawn per repository with the same per-command timeout, `GIT_TERMINAL_PROMPT=0` plus BatchMode ssh so a repository that needs a login fails fast instead of hanging the request on an invisible prompt — Codeman supplies no credentials, so a repository your own git is already signed in to works because that is your existing setup. A click joins a run already going for the same folder, and the click publishes what it got as the session's `gitFetch` state with `trigger: 'click'` (below), so another tab open on the same folder sees the same run.
 
 `data` is `{ state, repos, reposTruncated, repoLimit, fetchedAt }`, `repos[]` each `{ name, path, ok }` and, when it failed, `failure` (`{ code, message, stderr }`: the codes as in the clone failures, plus `NO_REMOTE`). A repository that could not be fetched keeps its row rather than being dropped. The panel shows the result under its list and then re-reads, so `behind` reflects what this fetch brought.
 
-The interval is two **synced** settings in `PUT /api/settings` (`src/git-fetch-scheduler.ts`): `gitFetchEnabled` (default `false`) and `gitFetchIntervalSeconds` (30 to 3600, default 300, the gap between runs timed from the start of a run so a slow repository does not push the next one out). Synced, not per-device, because the server is what acts on them; the scheduler reads them fresh on each 15 s tick, so a change works without a restart. A case can override both, and the override wins even while the app-wide switch is off: `POST /api/sessions/:id/git-fetch-settings` takes `{ "enabled": true | false | null, "intervalSeconds": number | null }` — `null` on a field clears that half so the app value applies again, a field left out of the body leaves the other half as it was — is `400 INVALID_INPUT` for a remote or Docker session, and answers `200` with `{ gitFetchSettings: { enabled, intervalSeconds } }` where `null` means the case follows the app. What the last run did rides the session state as `gitFetch` (`{ ranAt, trigger, state, repos, failed, firstFailure? }`, `trigger` is `click` or `interval`), on the existing `SessionUpdated` event: no new event. Remote and Docker cases are never fetched on a timer, and the Docker rule is re-checked against the CURRENT Docker roots every tick.
+The interval is two **synced** settings in `PUT /api/settings` (`src/git-fetch-scheduler.ts`): `gitFetchEnabled` (default `false`) and `gitFetchIntervalSeconds` (30 to 3600, default 300, the gap between runs timed from the start of a run so a slow repository does not push the next one out). Synced, not per-device, because the server is what acts on them; the scheduler reads them fresh on each 15 s tick, so a change works without a restart. A session can override both, and the override wins even while the app-wide switch is off: `POST /api/sessions/:id/git-fetch-settings` takes `{ "enabled": true | false | null, "intervalSeconds": number | null }` — `null` on a field clears that half so the app value applies again, a field left out of the body leaves the other half as it was — is `400 INVALID_INPUT` for a remote or Docker session, and answers `200` with `{ gitFetchSettings: { enabled, intervalSeconds } }` where `null` means the session follows the app. What the last run did rides the session state as `gitFetch` (`{ ranAt, trigger, state, repos, failed, firstFailure? }`, `trigger` is `click` or `interval`), on the existing `SessionUpdated` event: no new event. Sessions on the same folder share one run and both see its result, the schedule is keyed by folder, and a folder is fetched by at most one run at a time; every session open on a folder is remembered, so closing the one that holds the override does not stop that folder's fetching while another session is still open on it. The tick skips anything its bounded probe does not confirm is a directory, stamps each folder's schedule when it picks it, and does not run a second tick over a selection still going. Remote and Docker sessions are never fetched on a timer, and the Docker rule is re-checked against the CURRENT Docker roots every tick.
 
 ## Git worktrees of a case