chore(scripts): treat an expression-built script name as forbidden too (#2146)

Copilot, first review:

- The guard read only literal names, so `npm run smoke:web:${{ matrix.browser }}`
  and `npm run local:${{ matrix.task }}` walked past it — the one form in which
  a forbidden engine reaches CI without anyone typing its name. It already
  refused an expression-valued SMOKE_BROWSER for that exact reason; this applies
  the reasoning consistently. Its limit is now stated: a fully opaque
  `npm run ${{ matrix.script }}` names no family and is not detectable.
- The module header claimed the gate adds "the non-Chromium engine passes";
  it adds Firefox only, and WebKit belongs to neither tier.
- eslint.config.js:33 still said `npm run ci` — the last stale reference.
- AGENTS.md read "everything from `smoke` rightward is `local:gate` only",
  which is two claims wrong: smoke and Storybook run in GitHub CI too, and
  `pack:verify` is in neither tier.

Signed-off-by: Cliff Hall <cliff@futurescale.com>
Signed-off-by: cliffhall <cliff@futurescale.com>

AGENTS.md

@@ -929,7 +929,7 @@ The ⚠️ option-deletion hazard, the snapshot rule, and the recovery recipe ab
 - Run TUI tests with `npm run test` from `clients/tui/`
 - Run launcher tests with `npm run test` from `clients/launcher/`
 - Run the root tooling's own tests with `npm run test:scripts` from the root (this is also what runs the #2146 workflow guard against `.github/workflows/**`) — `node --test "scripts/**/*.test.mjs"`, node's built-in runner (the root has no vitest harness by design). A new `scripts/*.mjs` helper with pure logic gets a sibling `*.test.mjs`; keep the filename `*.test.mjs`, since `node --test` silently **skips** a file its glob misses and still exits 0 (`verify:typecheck-coverage` guards against exactly that).
-- **The test tiers, shallowest first:** unit (`test`, per client) → web integration (`test:integration`, real transports/servers) → out-of-process (`clients/cli/__tests__/e2e.test.ts`, spawns the built binary) → smokes through the built launcher (`npm run smoke`) → Storybook play functions (`test:storybook`) → the published-tarball check (`npm run pack:verify`, local/release only — needs network). `validate` runs the per-client `test` scripts — so web **unit** plus cli's out-of-process `e2e.test.ts` (it's part of cli's `test`), but **not** web's integration project, which runs inside the `coverage` gate. Everything from `smoke` rightward is `npm run local:gate` only, and is described under [Mandatory pre-push gate](#mandatory-pre-push-gate).
+- **The test tiers, shallowest first:** unit (`test`, per client) → web integration (`test:integration`, real transports/servers) → out-of-process (`clients/cli/__tests__/e2e.test.ts`, spawns the built binary) → smokes through the built launcher (`npm run smoke`) → Storybook play functions (`test:storybook`) → the published-tarball check (`npm run pack:verify`, local/release only — needs network). `validate` runs the per-client `test` scripts — so web **unit** plus cli's out-of-process `e2e.test.ts` (it's part of cli's `test`), but **not** web's integration project, which runs inside the `coverage` gate. Everything from `smoke` rightward is outside `validate` and is described under [Mandatory pre-push gate](#mandatory-pre-push-gate) — note that being outside `validate` is not the same as being local-only: `smoke` and the Storybook tests run in GitHub CI too, `pack:verify` is in neither tier (local/release only), and the genuinely gate-only steps are the two named in the [README's two-tier table](./README.md#two-tiers-github-ci-and-the-local-gate).
 - The repo root has no aggregate `test` script — each client self-validates, so run `npm run validate` from the root (all clients, fast) or `cd clients/<name> && npm run validate` (one client). Each client still exposes its own `test` / `test:coverage` for quick iteration.
 - **`validate` is fast: it runs `test`, not `test:coverage`.** The coverage gate (slower — adds v8 instrumentation, and for web the integration project) is a **separate** top-level `npm run coverage` (and per-client `coverage:web` / `coverage:cli` / `coverage:tui` / `coverage:launcher`, each delegating to that client's `test:coverage`). Run `npm run coverage` when you want to reproduce the gate locally before pushing. **CI runs `coverage`** on every push (#1550): the per-file ≥90 gate is CI-enforced, so a PR that drops any file below 90 on lines/statements/functions/branches fails the job. It runs in its **own job, in parallel with `build`** (#2159) — `coverage` consumes nothing `validate` produces, since each client's `test:coverage` builds whatever it needs itself, and running the two serially was 84% of a ~17m wall clock. Both publish jobs therefore gate on `needs: [build, coverage]`; leaving either off would let a release publish with the coverage gate red. Because web's `test:coverage` already runs the integration project, CI has no separate `test:integration` step — the integration paths are exercised inside the coverage gate.
 - Each client's `test:coverage` enforces a **uniform per-file gate of ≥ 90 on all four dimensions** — lines, statements, functions, and branches — across `clients/web`, `clients/cli`, `clients/tui`, and `clients/launcher` (CI enforces this gate). This is the result of a codebase-wide audit: the branch floor was first lifted 50 → 70 for web (#1271), then the whole gate raised to 90 with real tests added for every outlier. Genuinely-unreachable branches are **not** waved through by lowering the gate — they are annotated at the source with a justified `/* v8 ignore … -- <reason> */` comment. Acceptable reasons are happy-dom-inherent paths (Mantine portal mount points, `useMediaQuery` fallbacks, `typeof window` SSR guards), React StrictMode effect-replay blocks, and provably-dead defensive guards (e.g. a `?? fallback` for a value the types guarantee non-null, or a `Select.onChange` receiving a value outside the allowed list). New code must clear 90 on every dimension; reach for a justified `v8 ignore` only when a branch is genuinely impossible to exercise. The web coverage `include` (in `clients/web/vite.config.ts`) covers the shared `core/` runtime consumed by the browser — `core/mcp`, `core/react`, `core/auth`, `core/storage`, `core/logging`, `core/node`, **`core/json`, and `core/client`** (the last two folded in by #1689). When adding a `core/json/*` or `core/client/*` module, its tests live under `clients/web/src/test/core/…` and are gated the same ≥90 way.
@@ -1001,7 +1001,7 @@ Everything about the selection lives in **`scripts/lib/headless-browser.mjs`**
 - **An unrecognized `SMOKE_BROWSER` is an error, never a fallback.** Falling back to Chromium would report a green Chromium run under a job labelled `webkit` — coverage claimed but not run, which is worse than none.
 - **A launch failure names the engine that failed** and a remedy that works **from where the caller actually is**: `npm run smoke:web:<engine>`, or `npx playwright install --with-deps <engine>` run *from `clients/web`*. Naming `chromium` while WebKit was missing would send the reader to install a browser they already have — and naming a bare root-level `npx playwright` would send them to a version that is not the pinned one, which can install a browser revision the pinned Playwright still cannot launch.
 - **Firefox is gated locally, not in CI, and that asymmetry is deliberate.** A GitHub Actions job was trialled and removed. It was cheap — ~2 minutes, parallel with the 15-minute `build` job, so zero added wall-clock — but across a dozen runs Firefox never once disagreed with Chromium, so it spent runner minutes on every push, from every branch, carrying a real flake surface (`playwright install --with-deps` runs `apt-get update`, which fails whenever a third-party repo in the runner image breaks) to re-confirm a result already in hand. Moving it into `npm run local:gate` keeps the check where a human is about to push a change they can still reason about, and pays for it once rather than on every push. **Don't re-add the CI job on the argument that cross-engine coverage is good in principle** — that argument was accepted, and the pre-push gate is what serves it. Re-add it on evidence: a cross-engine regression that reached `v2/main` because someone skipped the gate.
-- **A guard enforces the split, so it cannot be undone by accident (#2146).** `scripts/lib/workflow-gate.mjs` is run by `npm run test:scripts` over every file under `.github/workflows/`, and fails the suite on: an invocation of a `local:*` script (the prefix *means* local-only, so a future sibling is covered without editing the guard); an invocation of a non-Chromium engine pass, derived from `SUPPORTED_BROWSERS` so a fourth engine extends the guard rather than opening a hole in it; an invocation of `smoke:web:engine`, whose engine comes from the environment and so cannot be read off the workflow at all; or `SMOKE_BROWSER` set to anything but a literal `chromium` — the back door that would redirect an otherwise innocent `npm run smoke`. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui`: those belong in CI and are there today, and `smoke:tui` self-skips under `process.env.CI` on its own. Lines that are comments are not scanned — a comment invokes nothing, and a guard that made the workflow undocumentable would be traded for the wrong thing.
+- **A guard enforces the split, so it cannot be undone by accident (#2146).** `scripts/lib/workflow-gate.mjs` is run by `npm run test:scripts` over every file under `.github/workflows/`, and fails the suite on: an invocation of a `local:*` script (the prefix *means* local-only, so a future sibling is covered without editing the guard); an invocation of a non-Chromium engine pass, derived from `SUPPORTED_BROWSERS` so a fourth engine extends the guard rather than opening a hole in it; an invocation of `smoke:web:engine`, whose engine comes from the environment and so cannot be read off the workflow at all; or `SMOKE_BROWSER` set to anything but a literal `chromium` — the back door that would redirect an otherwise innocent `npm run smoke`. A name built from a workflow **expression** counts as forbidden too (`smoke:web:${{ matrix.browser }}`, `local:${{ matrix.task }}`): a matrix the guard cannot read may well contain `firefox`, so an unreadable name is not waved through. Its limit is worth knowing — a fully opaque `npm run ${{ matrix.script }}` names no family at all and is not detectable. It deliberately does **not** forbid `npm run smoke`, `smoke:web:chromium`, or `smoke:tui`: those belong in CI and are there today, and `smoke:tui` self-skips under `process.env.CI` on its own. Lines that are comments are not scanned — a comment invokes nothing, and a guard that made the workflow undocumentable would be traded for the wrong thing.
 - **This makes `npm run local:gate` a strict superset of GitHub CI rather than a mirror of it.** That was already the direction (`smoke:tui` self-skips on CI and runs only locally); Firefox is the second such step. The invariant that still holds, and the one that matters, is the useful direction: **passing `npm run local:gate` locally means CI's gates will pass.**
 - **`pack:verify` stays pinned to Chromium**, passing it explicitly rather than reading `SMOKE_BROWSER`. It is a _packaging_ check; the engine question belongs where the sandbox is under test, and pinning it also means it can't be pointed at an engine its npm script never installed.
 - **WebKit fails the two App smokes**, for reasons nobody has identified — the failure stage even varies between runs. The investigation was dropped as not worth the effort once it became clear it does not reproduce in real Safari, and that an isolated repro of the suspected mechanism did not reproduce it under Playwright's WebKit either. Treat a WebKit failure as unexplained rather than as a defect until someone has actually looked.