feat(ai-router): test an endpoint before saving it, and re-point a live lane

Two gaps left by the AI Router feature: a profile could be saved without ever
being reachable, and a lane's router could only be chosen at creation.

**POST /api/ai-routers/test** answers the question saving cannot. It sends one
Anthropic-style message capped at a single output token to `<baseUrl>/v1/messages`
with a 15s timeout — the wire shape a claude lane's eight env keys point at, so
what is tested is what will actually run. A router that answers is a 200 here
whatever it replies: `{ ok, status, message }` carries the router's own words,
and `status` is null when nothing answered at all. Only bad input is a 4xx.

The stored key is only ever sent to the endpoint it was stored against. A blank
`apiKey` falls back to the key of the profile named by `name`, but only while
the submitted `baseUrl` still equals the saved one — so testing a retyped
endpoint needs a retyped key (`EBADKEY`). Without that rule this route would be
a way to make the server POST a saved API key to any URL a browser names.

Network failures report `error.cause`, not `error.message`: node's fetch reports
every transport failure as the same useless "fetch failed" and hides the part
the user can act on (ECONNREFUSED, ENOTFOUND, a TLS error) one level down.

**The lane card carries an AI Router select.** The Add-lane modal was the only
place a router was chosen, and a lane outlives its creation. Switching goes
through `POST /api/lanes/:id/router/apply` — never a lane PATCH — because the
DB column and the lane's own config on disk may only move together. A failed
apply puts the select back rather than leaving the card claiming a router the
lane did not get. Hidden when `native` is the only profile: a select with one
option is a control that cannot do anything.

Adds `Lane.router_profile` to the client type (the payload already carried it).

CLAUDE.md

@@ -1,6 +1,6 @@
 # Claude Code Working Guide
 
-_Last synced: v1.6.0 (2026-09-14) + AI Router profiles (`server/lib/ai-routers.js`, `server/lib/router-apply.js`, the Settings tab `/settings?tool=ai-router`, and `lanes.router_profile`) + the bootstrap's superseded-build guard and plugin-cache pruner (`supersededBy`/`pruneRetiredPluginRoots` in `scripts/plugin-bootstrap.js`, `unitRoot` in `scripts/systemd-service.js`) + v1.5.6 (2026-09-11) + the systemd handover rule below (`scripts/systemd-service.js`'s `writeUserService`/`restartUserService` split and `plugin-bootstrap.js`'s deferred `pendingSystemdRestart`) + eb63569 (2026-09-10) + release-based update detection (`server/lib/update-check.js` reads the forge releases API — a checkout via its `origin` remote, a plugin-cache install via the marketplace manifest on disk, since an archive-sourced cache dir has no `.git`; a `plugin_managed` install self-updates via the detached `plugin-update` chain) + the install-wide **Update all** batch and session reload (`server/lib/cc-update-all.js`, `server/lib/cc-reload.js`)._ 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: v1.6.0 (2026-09-14) + AI Router profiles (`server/lib/ai-routers.js`, `server/lib/router-apply.js`, the Settings tab `/settings?tool=ai-router`, its **Test** button / `POST /api/ai-routers/test`, the per-lane router select on `LaneCard`, and `lanes.router_profile`) + the bootstrap's superseded-build guard and plugin-cache pruner (`supersededBy`/`pruneRetiredPluginRoots` in `scripts/plugin-bootstrap.js`, `unitRoot` in `scripts/systemd-service.js`) + v1.5.6 (2026-09-11) + the systemd handover rule below (`scripts/systemd-service.js`'s `writeUserService`/`restartUserService` split and `plugin-bootstrap.js`'s deferred `pendingSystemdRestart`) + eb63569 (2026-09-10) + release-based update detection (`server/lib/update-check.js` reads the forge releases API — a checkout via its `origin` remote, a plugin-cache install via the marketplace manifest on disk, since an archive-sourced cache dir has no `.git`; a `plugin_managed` install self-updates via the detached `plugin-update` chain) + the install-wide **Update all** batch and session reload (`server/lib/cc-update-all.js`, `server/lib/cc-reload.js`)._ 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.
@@ -36,7 +36,7 @@ A **lane** is a durable unit of parallel agent work — one working directory, m
 - Liveness: a silent **watcher** (stage matching `/watch|poll/`) is dead after `LANE_DEAD_SEC` seconds (default 300); a silent **idle** lane is at rest, not dead.
 - **Never `rm -rf` a lane.** Destructive lane operations (`reset`, `remove`, `purge`) go through `server/lib/worktree.js`/`server/lib/lanes.js`, never a raw filesystem delete — that's what keeps the three-check destroy guard and the DB bookkeeping in lockstep.
 - **Never build a git command as a shell string.** Lane git operations use `execFile("git", [...args])` with an explicit argument array (see `server/lib/worktree.js`'s `git()` helper), never a concatenated/interpolated string passed to a shell.
-- **A lane's AI Router profile is a lane fact too, and it never travels alone.** `lanes.router_profile` (nullable; null means the same as `native`) is written ONLY by `setRouterProfile`, called beside the disk write in `POST /api/lanes/:id/router/apply` — never through `PATCHABLE`. The column and the lane's own config must move together, or the row claims a router the lane's `settings.local.json` has never heard of. What is written comes from the lane row, never the request: a **claude** lane gets eight `env` keys merged into `<cwd>/.claude/settings.local.json` (`.local` because the value carries an API key; every other key in that file is preserved and a non-JSON file is refused, not rewritten), a **codex** lane gets `$CODEX_HOME/<name>.config.toml` — the layer `codex -p <name>` loads — because Codex has NO project-level config, and its base `config.toml` is never touched. Key material never leaves the server: profiles live at `<CLAUDE_HOME>/agenthub-routers/` (0700/0600), `GET /api/ai-routers` reports only `hasKey`, and there is deliberately no route that returns one profile in full. **Codex's key reaches the pane through tmux's `-e` argv and is never typed into it** — `tmux.sendCommand` takes over an idle pane with `respawn-pane` for exactly this reason; a `KEY='sk-…' codex …` line typed with `send-keys` would be rendered to every attached browser, kept in the scrollback and appended to the user's shell history. Do not reintroduce a typed command line there. **And attaching COPIES a profile**, so the store stops being the single source of truth the moment a lane exists: `PATCH`/`DELETE /api/ai-routers/:name` must push through to the lanes naming it (`reapplyToLanes`/`detachFromLanes`), or a rotated key silently never reaches the lane still using the revoked one. See `server/lib/ai-routers.js`, `server/lib/router-apply.js`.
+- **A lane's AI Router profile is a lane fact too, and it never travels alone.** `lanes.router_profile` (nullable; null means the same as `native`) is written ONLY by `setRouterProfile`, called beside the disk write in `POST /api/lanes/:id/router/apply` — never through `PATCHABLE`. The column and the lane's own config must move together, or the row claims a router the lane's `settings.local.json` has never heard of. What is written comes from the lane row, never the request: a **claude** lane gets eight `env` keys merged into `<cwd>/.claude/settings.local.json` (`.local` because the value carries an API key; every other key in that file is preserved and a non-JSON file is refused, not rewritten), a **codex** lane gets `$CODEX_HOME/<name>.config.toml` — the layer `codex -p <name>` loads — because Codex has NO project-level config, and its base `config.toml` is never touched. Key material never leaves the server: profiles live at `<CLAUDE_HOME>/agenthub-routers/` (0700/0600), `GET /api/ai-routers` reports only `hasKey`, and there is deliberately no route that returns one profile in full. **`POST /api/ai-routers/test` sends a stored key ONLY to the endpoint it was stored against** — a blank `apiKey` falls back to the profile named by `name`, but only while the submitted `baseUrl` still equals the saved one, else `EBADKEY`. Relax that and the route becomes a way to make the server POST a saved key to any URL a browser names. **Re-pointing a lane is allowed and is not a PATCH:** the lane card's AI Router select calls `POST /api/lanes/:id/router/apply` (column + disk together, same rule as above), never `PATCH /api/lanes/:id`. **Codex's key reaches the pane through tmux's `-e` argv and is never typed into it** — `tmux.sendCommand` takes over an idle pane with `respawn-pane` for exactly this reason; a `KEY='sk-…' codex …` line typed with `send-keys` would be rendered to every attached browser, kept in the scrollback and appended to the user's shell history. Do not reintroduce a typed command line there. **And attaching COPIES a profile**, so the store stops being the single source of truth the moment a lane exists: `PATCH`/`DELETE /api/ai-routers/:name` must push through to the lanes naming it (`reapplyToLanes`/`detachFromLanes`), or a rotated key silently never reaches the lane still using the revoked one. See `server/lib/ai-routers.js`, `server/lib/router-apply.js`.
 - **A lane's `tool` is a lane fact, immutable, and never read from a request.** `lanes.tool` (`claude` | `codex`, default `claude`) is set by `createLane` only — it is deliberately absent from `PATCHABLE`, so no PATCH can flip the CLI under a live pane. Every spawn path (`POST /api/lanes/:id/start`, `POST /api/run`) takes the tool from the lane row and ignores whatever the body says; the run panel's Codex-only fields (`sandbox`, `approval`, `resumeLast`) are validated against the fixed allowlists in `server/lib/pty-run.js` before they reach an argv, and the bypass flags (`--dangerously-bypass-approvals-and-sandbox`, `--dangerously-bypass-hook-trust`) are never emitted. `GET /api/run/binary?tool=` resolves the probed binary name from that same allowlist — the query string reaches `which`.
 - **Adopted lanes are not destroyable.** A lane with `kind === "adopted"` may never have its worktree reset or removed; "removing" one only drops the dashboard's own record of it. This is enforced in code (`assertDestroyable`'s first check) — do not add a path that bypasses it.
 - **A `cwd` can back at most one lane per tool, not one lane overall.** Uniqueness is the composite `idx_lanes_cwd_tool` (`cwd`, `tool`), not `cwd` alone — Repo/Adopt mode (`POST /api/lanes/ensure`) lets the same directory carry a `claude` lane and a `codex` lane side by side, shown as two separate cards. `resolveLaneByCwd(cwd, tool)` takes an optional `tool` filter for exactly this; hook ingestion (`touchLaneFromHook`, `resolveLaneForWork`) always pins it to `"claude"` because Codex has no hook mechanism in this codebase, so a hook event must never touch a `codex` lane sharing the path. Worktree mode is unaffected — it already allocates a unique directory per lane.