e2e/CI: dual-engine suites, per-engine screenshots, SwiftShader retired, prod web suite, CI-coverage gate

Squash of experiment/ff-big-modules vs main.

Big-module routing removed: native-EH shrank kicad_editor below
SpiderMonkey's x86-64 code budget (runs 29355049705/29356152413 green on
stock Firefox), so BIG_MODULE_SPECS routing and the baseline-only-JIT
crutch are gone — kicad-firefox and kicad-chromium both run the full
suite, with the module compiled the way real users' browsers compile it.

Per-engine screenshots end to end: stableShot/shotPath write
test-results/<engine>/<name>.png; baselines move to
baseline-screenshots/{chromium,firefox}/ and the whole tools/screenshots
pipeline (compare/promote/manifest/spec-map/changelog/Discord) keys on
<engine>/<name>. Previously Firefox and Chromium renders of one spec
overwrote each other and Firefox renders were never actually gated.
Seeded from CI run 29421380806 (92 new firefox baselines, +24 chromium
web-suite shots); manifest generated from the baseline tree.

One merged playwright.config.ts (kicad/asyncify/coroutine/perf as
projects); ~25 dead npm scripts dropped. The web suite is gated in CI for
the first time ever (4 rotted specs fixed, 5 broken lib-bridge specs
triaged as fixme in docs/features/web-e2e-rot/); cheap lint step after
npm ci; last 26 blind-sleep violations fixed.

SwiftShader retired: CI Chromium renders WebGL on ANGLE → Mesa llvmpipe
(--use-gl=angle --use-angle=gl --ignore-gpu-blocklist; the blocklist flag
is mandatory — llvmpipe is blocklisted and WebGL is silently unavailable
without it) in BOTH configs. Under WORKERS=4 congestion SwiftShader
transiently failed the first post-board-load draw and the recovery
cascade ended in a silent permanent Cairo fallback — that engine flip was
the "~1.2% changedRatio both directions" occ-export baseline flake.
Validated 160/160 across two 80-repeat rigs; full analysis in
docs/features/wx-parity-bugs/occ-export-context-eviction.md. Chromium
baselines shift slightly on llvmpipe — promote once from the first green
run. Deflakes the new coverage exposed: presence baselines settle before
capture; presence fixtures declare current file formats; perf gets its
own outputDir so CI evidence survives; occ-export settles the board paint
before the export dialog; menu-item waits (waitForRenderedByLabel before
clickMenuItem) in 4 specs + the TESTING.md rule.

Web suite runs the PROD build, in parallel: webServer becomes backend
`start` + the standalone's e2e:preview (build-preview.mjs: link-wasm →
stash the public/wasm symlink aside during vite build, build-demo.mjs's
move — then vite preview as the persistent server). The wasm middleware
serves /wasm/* in preview and emits COOP/COEP/CORP itself (a pthread
worker script's own response must carry COEP or Chrome kills it with
ERR_BLOCKED_BY_RESPONSE). VITE_* flags bake at build time;
VITE_ALLOW_USER_OVERRIDE joins turbo globalEnv. fullyParallel + default
workers: 5.2m → 1.4m. Determinism fixes the parallel run exposed:
shared-page specs become serial groups; locks.spec grabs alice's exact
item via the new kicadCollabTestSelectByUuid hook (cross-tab "first
footprint" order is not a ysync invariant); quit specs poll page.url()
(quit supersedes its own navigation — NS_BINDING_ABORTED on Firefox).
Suite: 51 passed / 12 skipped / 0 failed in 1.6m.

CI-coverage gate (lint:ci-coverage): every tests/**/*.spec.ts must be
reachable from the npm scripts the workflows invoke — scraped from
.github/workflows/, resolved through package.json, coverage asked from
playwright --list itself. Rules: uncovered-spec + orphan-project (with a
documented LOCAL_ONLY_PROJECTS allowlist). Gating next to
lint:determinism; 138 spec files / 13 projects accounted for.

Product fixes kept from the investigations (reachable on real GPUs too):
wx 7799fd1be5 — paint flags clear before dispatch + Invalidate always
propagates; kicad 3dcfea5e45 — SwiftShader pass-boundary flush +
per-instance font texture + first-frame GL-error drain (GAL recovery
recovers instead of falling back to Cairo) + the user-facing eeschema
switch navigates again under __EMSCRIPTEN__ (project-sync's
FaceRegistered gate had rerouted it into the hidden sync player; caught
by the newly-gated web suite).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018eUxiPApHgGiu9NFyQfhAq

tests/TESTING.md

@@ -1,8 +1,11 @@
 # Testing rules
 
 Determinism rules for the Playwright specs (`tests/e2e`, `tests/kicad`, `tests/web`).
-Enforced by `npm run lint:determinism` (`tools/lint-determinism.ts`). Run specs from `tests/`
-via `npm run test:kicad` (firefox) / `npm run test:e2e` (chromium) — not playwright directly.
+Enforced by `npm run lint:determinism` (`tools/lint-determinism.ts`, gating in CI). Run specs
+from `tests/` via `npm run test:e2e` (the full CI project set: wx-chromium, kicad-firefox,
+kicad-chromium, asyncify-firefox, coroutine-firefox) or `npm run test:kicad` (kicad-firefox
+only) — not playwright directly. One spec on one engine:
+`npx playwright test --project=kicad-firefox kicad/pcbnew.spec.ts`.
 
 ## Waits — never blind
 
@@ -14,6 +17,13 @@ via `npm run test:kicad` (firefox) / `npm run test:e2e` (chromium) — not playw
 - The **only** allowed `waitForTimeout` is an irreducible interaction dwell — a canvas/keyboard
   commit with no JS-observable signal — and it MUST carry a same-line marker:
   `// eslint-disable-line -- documented interaction dwell: <why>`.
+- **Menu clicks: wait for the specific item, not a count.** Popup items register in the element
+  registry progressively as they paint, so a coarse gate ("N menuitems rendered") can pass before
+  the item you're about to click exists — and `clickMenuItem` is single-shot. Before every
+  `clickMenuItem(page, 'X')`, `await waitForRenderedByLabel(page, 'X', { elementType: 'menuitem' })`
+  (same matcher as the click). `clickMenuItemByText` already waits internally and needs no guard.
+  A submenu click needs its own wait: the parent menu's still-rendered items satisfy any count gate
+  before the submenu paints.
 
 ## No defensive branches
 
@@ -26,10 +36,16 @@ via `npm run test:kicad` (firefox) / `npm run test:e2e` (chromium) — not playw
 ## Screenshots — `stableShot`, compared offline
 
 - Capture with **`stableShot(page, 'name.png', { fullPage })`** — it settles the render (in-page
-  canvas-hash over animation frames) then writes a raw PNG to `test-results/`. It does **not**
-  assert. Never use Playwright's `toHaveScreenshot`.
-- Comparison is offline: `npm run screenshots:check` diffs `test-results/` against the committed
-  baselines in `tests/baseline-screenshots/` (+ `3d-regression/`, `gal-regression/`).
+  canvas-hash over animation frames) then writes a raw PNG to
+  `test-results/<engine>/` (`chromium`/`firefox`, derived from the running browser — the same
+  spec on two engines writes two files). It does **not** assert. Never use Playwright's
+  `toHaveScreenshot`. Raw `page.screenshot`/fs writers must route through
+  `shotPath(page, 'name.png')` for the same engine scoping.
+- Comparison is offline and per-engine: `npm run screenshots:check` diffs
+  `test-results/<engine>/` against the committed baselines in
+  `tests/baseline-screenshots/<engine>/` (+ `3d-regression/`, `gal-regression/`).
+  `tests/screenshot-manifest.json` (regen: `npm run screenshots:manifest`) is the authoritative
+  {name, engine} list — CI fails the lint step if it drifts from the baseline tree.
 - **CI's Linux render is the source of truth**; baselines are promoted from CI
   (`npm run screenshots:promote -- --run <ci-run-id>`). A local (Mac) check shows font/render
   noise and is not the gate.
@@ -37,9 +53,27 @@ via `npm run test:kicad` (firefox) / `npm run test:e2e` (chromium) — not playw
 
 ## Retries
 
-- **`retries: 0`** in both configs. A failure is real; don't mask it with a retry.
+- **`retries: 0`** in both configs (`playwright.config.ts` — the merged wasm-suite config —
+  and `playwright-web.config.ts`). A failure is real; don't mask it with a retry.
+
+## Every spec runs in CI — `lint:ci-coverage`
+
+`npm run lint:ci-coverage` (`tools/lint-ci-coverage.ts`, gating in CI next to the
+determinism lint) proves every `*.spec.ts` under `tests/` is actually executed by CI:
+it scrapes the `npm run test:…` invocations from `.github/workflows/`, resolves them
+through `package.json` to their `playwright test --config/--project` flags, and asks
+Playwright itself (`--list`) which files those runs cover. No hand-maintained lists —
+adding a spec in a brand-new directory is exactly what it catches.
+
+When it fires:
+- `uncovered-spec` — your new spec matches no CI-run project. Put it in a covered
+  `testDir`, adjust a project's `testMatch`, or add the project to a CI npm script.
+- `orphan-project` — you added a config project no CI script selects. Wire it into a
+  CI script, or (for deliberately-local system-browser projects) add it to
+  `LOCAL_ONLY_PROJECTS` in the lint with a comment saying why.
 
 ## Where things are
 
 - Per-test logs (JS console + cpp): `tests/logs/{wxwidgets,kicad}/<test-name>/`.
-- Guard: `npm run lint:determinism`. Screenshot gate: `npm run screenshots:check`.
+- Guards: `npm run lint:determinism`, `npm run lint:ci-coverage`.
+  Screenshot gate: `npm run screenshots:check`.