Deployment blocker: consolidate Classroom API functions below Vercel Hobby limit #321

Problem

Production is not currently publishing the merged Classroom work.

Vercel production deployments:

• Add Instructor-run live classroom management #314 merge b141d55050207e4cf7ce842a4452a220a5268968 -> ERROR
• Add staged classroom simulation and debrief orchestration #315 merge 7c6afa4069ac5de5eae8ec0c9b0959084650c93a -> ERROR

Vercel reports:

No more than 12 Serverless Functions can be added to a Deployment on the Hobby plan.

The last READY production deployment is #308 at 6c58336ac1677764641c09eadb201abcad8eeac1.

This is a deployment-architecture limit, not a GitHub CI/product-test failure.

Cause

The Classroom API grew through safe, focused route files. At #308 the repository had 15 JavaScript files under api/, with helper/server-only modules not emitted as route functions and 11 routable endpoints. #312 added four live-management route entrypoints; #313 added four staged-exercise route entrypoints. The resulting routable function count exceeds the Hobby limit.

Goal

Preserve all existing public API URLs and authorization behavior while reducing emitted Vercel Serverless Functions to <=12, preferably with substantial headroom.

Preferred architecture

Consolidate Classroom route entrypoints behind one Classroom dispatcher/serverless function and Vercel rewrites, while keeping the existing domain handlers in api/_classroom.js, api/_classroomExercise.js, and api/_protectedCaseStudies.js.

• clients keep their existing URLs;
• rewrite only at deployment routing;
• dispatch to the existing handler factories;
• keep workspace collaboration routes separate;
• helper modules remain server-only;
• add guard/tests that fail if the emitted/routable function count grows beyond the Hobby budget again.

Must preserve

• Instructor vs Student capability isolation;
• Student non-enumeration;
• stable Student class-session vs workspace-edit authority;
• protected Case Study access and staged full-payload denial;
• exercise lifecycle/revision semantics;
• checkpoint authorization;
• HTTP 423 frozen Student write policy;
• Standalone/ad-hoc collaboration routes;
• deterministic browser fixture paths;
• no public protected-case leakage.

Deployment acceptance

• GitHub quality/browser/security checks green;
• Vercel production deployment for the hotfix merge reaches READY;
• production deployment corresponds to the exact main commit;
• protected authored template JSON/internal docs remain absent from public static output;
• production runtime error scan is clean after deploy.

Priority

P0 publish blocker. Complete this before #316.

Active recovery PR

• PR Consolidate Classroom API to restore Vercel production deployment #322 — Consolidate Classroom API to restore Vercel production deployment
• Branch: fix/vercel-classroom-function-budget
• Public URLs remain unchanged through Vercel rewrites.
• Current conservative deployable function count after consolidation: 5 / 12.
• Do not close this issue until the exact merged main SHA is Vercel production READY.

Closeout — production restored

• PR Consolidate Classroom API to restore Vercel production deployment #322 merged to main as 21bff1d1c5a70caff0aa94aadd58abcb0644f397.
• Exact PR-head verification deployment dpl_87aJLUvqaSc3wQ45gecTiGVMdCVq reached READY from verify/function-budget-hotfix at 9094a3fa2a56c8720e9c149278ef03165ecd0b17.
• Verification build reported 5/12 conservative Serverless Function candidates and re-verified the protected/public Case Study boundary.
• Exact merged-main production deployment dpl_VZoSoWJsDs6Eb727EN5hmrFSgAcA reached READY for 21bff1d1c5a70caff0aa94aadd58abcb0644f397.
• Post-deploy Vercel runtime-error scan: clean.
• Classroom follow-on: Instructor-run live class, roster, and dynamic team management #312/Classroom follow-on: Instructor-orchestrated case simulation and staged debrief #313 Classroom functionality is now production-published.
• Classroom follow-on: Protected staged case assets and rich Student case rendering #316 is unblocked and becomes the next implementation issue.