test(e2e): web-app tool open-path suite + pl_editor open/wizard-skip

Add an e2e suite that drives the real React web app (not the standalone
harness): tests/playwright-web.config.ts + tests/web/tools-open.spec.ts navigate
/p/demo/<tool>/<file> for all five tools and assert each boots, opens its demo
file (title drops "untitled"), shows no first-run wizard, and emits no WASM abort
or URL-regex modal. global-setup-web.ts re-seeds the demo project through the API
if missing, so the suite is self-sufficient against a running dev stack. Wired as
`npm run test:web`.

Also at the harness level:
- pl_editor-load.spec.ts: prove the pl_editor kicadOpenFile embind hook opens a
  .kicad_wks (mirrors eeschema-load.spec.ts).
- seed KiCad config in pl_editor.html / symbol_editor.html (matching eeschema.html
  and the web app's boot.ts) so the harness boots wizard-free; repurpose
  pl_editor.spec.ts's stale "wizard completes" test into a wizard-skip regression.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/package.json

@@ -9,6 +9,8 @@
     "build-wasm": "cd apps && make -f Makefile.wasm",
     "serve": "npx serve apps -p 8080 -c ../serve.json",
     "setup:kicad": "./scripts/setup-kicad-wasm.sh",
+    "test:web": "npm run setup:kicad && playwright test --config=playwright-web.config.ts --project=firefox",
+    "test:web:headed": "npm run setup:kicad && playwright test --config=playwright-web.config.ts --project=chromium --headed",
     "test:kicad:firefox": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=firefox",
     "test:kicad:chrome": "npm run setup:kicad && playwright test --config=playwright-kicad.config.ts --project=chromium --headed",
     "test:kicad": "npm run test:kicad:firefox",