Add reproducible browser and accessibility gates

docs/spec/testing.md

@@ -27,6 +27,32 @@ same-origin credentials, encoding, binary bodies, response headers, declared
 and undeclared failures, network failures, and the no-automatic-retry policy.
 `make check-product` runs this gate before its kind product lane.
 
+## Browser behavior and accessibility
+
+`make check-browser` runs the browser unit and component tests, strict
+TypeScript and Svelte diagnostics, the production Vite build, and one
+Playwright journey against compiled assets served by the real Haskell
+application. The reference lane uses Redis, Keycloak, and Garage from the
+isolated kind fixture.
+
+Vitest 4.1.10 with Testing Library owns component behavior. Playwright 1.61.1
+with Chromium and axe-core 4.12.1 owns rendered accessibility and critical
+product journeys. The browser runner installs the Chromium revision selected
+by the pinned Playwright package before creating the fixture; the host
+provides Playwright's supported Linux shared libraries. The browser gate
+covers authenticated startup, active-root state, keyboard operation,
+browsing, bounded partial search, upload failure and retry, worker-backed
+upload, download, single-delete focus recovery, persisted recursive-delete
+recovery, logout, and production asset loading. Accessibility checks cover
+programmatic names, roles, states, focus, keyboard operation, and serious or
+critical axe findings, including rendered color contrast.
+
+Playwright retains traces, screenshots, and video for failures under
+`web/test-results/`; its HTML report is written under `web/playwright-report/`.
+Both directories are disposable and ignored. The fixture authentication file
+contains only synthetic credentials, is mode-restricted, and is removed by
+the runner.
+
 ## Model correspondence
 
 `make check-model-correspondence` runs before the kind protocol-conformance