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/README.md

@@ -19,17 +19,21 @@ This builds `apps/minimal_test.{html,js,wasm}` and standalone test apps.
 
 ```bash
 npm install
-npm test          # wx e2e specs + the asyncify race harness
+npm test          # setup:kicad + the full merged run (same projects as CI)
 ```
 
-KiCad application tests are a separate, heavier suite (they need the
-docker-built KiCad WASM): `npm run test:kicad`. Run only the wx e2e specs with
-`npm run test:wx`.
+One merged config (`playwright.config.ts`) drives every wasm suite as
+Playwright *projects*; `npm run test:e2e` runs the CI set: `wx-chromium`,
+`kicad-firefox`, `kicad-chromium`, `asyncify-firefox`, `coroutine-firefox`.
+The KiCad specs (heavier — they need the docker-built KiCad WASM) run on BOTH
+engines; `npm run test:kicad` is the firefox-only shortcut. The React web app
+suite is separate: `npm run test:web` (see `playwright-web.config.ts`).
 
-To run specific tests:
+To run a subset, pick a project (and optionally a spec):
 ```bash
-npx playwright test menu.spec.ts        # Run menu tests only
-npx playwright test --grep "wxTimer"    # Run tests matching pattern
+npx playwright test --project=wx-chromium menu.spec.ts     # wx menu tests only
+npx playwright test --project=kicad-firefox kicad/pcbnew.spec.ts
+npx playwright test --project=wx-chromium --grep "wxTimer"
 ```
 
 ## Test Structure
@@ -49,12 +53,14 @@ tests/
 │   ├── wxwidgets.spec.ts   # Comprehensive UI interaction tests
 │   └── ...
 ├── logs/                   # Test logs (auto-generated)
-├── test-results/           # Screenshots (auto-generated)
-├── baseline-screenshots/   # Reference screenshots for comparison
+├── test-results/{chromium,firefox}/   # Screenshots per engine (auto-generated)
+├── baseline-screenshots/{chromium,firefox}/  # Committed reference screenshots per engine
+├── screenshot-manifest.json # Authoritative {name, engine} list (npm run screenshots:manifest)
 ├── apps/              # Built WASM test applications
 │   ├── minimal_test.html  # Main test app
 │   └── standalone/        # Individual component test apps
-└── playwright.config.ts   # Playwright configuration
+├── playwright.config.ts       # THE merged config (wx / kicad / asyncify / coroutine / perf projects)
+└── playwright-web.config.ts   # React web-app suite (own server stack)
 ```
 
 ## Logging
@@ -76,10 +82,15 @@ Example log format:
 
 ## Screenshots
 
-Tests capture screenshots to `test-results/`. Compare against baselines:
+Tests capture raw PNGs to `test-results/<engine>/` (engine-scoped via
+`stableShot`/`shotPath`). The offline gate compares them against the committed
+per-engine baselines:
 ```bash
-../scripts/compare-screenshots.sh
+npm run screenshots:check
 ```
+CI's Linux render is the source of truth — update baselines by promoting a CI
+run (`npm run screenshots:promote -- --run <ci-run-id>`), never by copying
+local renders. Rules and details: `TESTING.md`.
 
 ## Viewing the App Directly