[MajorIncident]

Program / issues

• Program: Classroom experience program: Standalone, Student, and Instructor #288
• Classroom browser/security slice: Classroom 8/8: Browser E2E, accessibility, and CI protection for role/classroom journeys #296
• Shared Playwright/accessibility foundation: Add critical-path Playwright and accessibility regression suite #279
• Base: main at merged Protect Classroom Case Study delivery #307 (09f034f1f1776a3aaf92be7dec86b902549c8eb9)
• Branch: feature/classroom-browser-e2e

Closes #296
Closes #279

Outcome

Adds one deterministic real-browser quality layer for Standalone, Student, and Instructor behavior without depending on Vercel feature previews or production credentials.

The final browser matrix covers:

• first-run experience selection and accessibility;
• Standalone input -> summary -> persistence/reload;
• Templates-only Standalone resources;
• real Save to File -> mutate -> Load from File round trip, including Intake-mode restoration;
• mobile Standalone and Classroom entry smoke;
• Student class join/resume;
• same-team multi-browser synchronization and cross-workspace isolation;
• Instructor roster navigation, workspace switching, read-only observation, and resume;
• Instructor coaching -> Student read-only feedback -> changed-since-review;
• protected Case Study unauthorized catalog/payload rejection and authorized apply flow;
• invalid authority, expired Student resume, and Student non-enumeration;
• serious/critical axe checks and uncaught-page-error protection on covered journeys.

Browser execution contract

• Playwright 1.63 + axe 4.13.
• Desktop Chromium + Pixel 7 projects.
• scripts/serve-browser-tests.mjs provides a deterministic local HTTP/API fixture.
• Stateful Classroom fixtures are isolated by spec/project/retry so fully parallel runs cannot share mutable workspace/coaching state.
• Traces/screenshots are retained only on failure.
• Normal PR validation does not depend on Vercel preview availability or build quota.

Required CI decision

Browser regression is required, not advisory.

The existing branch-protected tests status now:

1. runs npm run quality;
2. installs Chromium;
3. runs npm run test:browser.

This preserves the existing protected status context rather than requiring a repository-rules migration. The separate Browser E2E (manual) workflow remains available only for focused diagnostics.

Final documented head: eba5f5139195f9df9de54f25093ed80f5b01e064.

Validation on the final head:

• tests / CI: green, including 22 browser tests passed / 6 intentional project-scoped skips / 0 failed;
• CodeQL: green;
• Dependency Review: green;
• Template Manifest Guard: green;
• PR review threads: none;
• compare to main: 101 ahead / 0 behind;
• changed files are confined to browser infrastructure/tests, browser-discovered accessibility/runtime fixes, CI integration, and supporting documentation.

Product fixes discovered by real-browser coverage

The suite found and protected fixes for:

• resource chooser ARIA structure;
• Apply-resource contrast;
• Student admission layout interception;
• footer/resource/action/presence contrast;
• closed Templates drawer inertness;
• invalid generic-container aria-readonly;
• collaboration presence badge contrast;
• deterministic fixture isolation under fully-parallel Playwright execution.

Guardrails

• Node/jsdom remains the fast canonical module/API layer.
• Standalone remains backend-optional.
• Browser fixtures contain no production credentials/secrets.
• Protect Classroom Case Study delivery #307 protected Case Study boundaries remain intact.
• Current class+assignment-code Student admission is transitional; tests protect authorization/non-enumeration without making that UX permanent.

Cold restart / next product direction

Read docs/classroom-workstream.md, docs/classroom-roadmap.md, and docs/testing-guidelines.md.

After this PR:

1. Classroom follow-on: Instructor-run live class, roster, and dynamic team management #312 — Instructor-run live class, one-code Student admission, waiting/late roster, accessible team formation/reassignment, automatic workspace switching, and high-signal team monitoring.
2. Classroom follow-on: Instructor-orchestrated case simulation and staged debrief #313 — Instructor-orchestrated staged Case Study simulation, progressive protected content release, pause/debrief/advance, and case reference beside Intake.

#313 should build on #312 rather than bypassing the live-class/team-management substrate.