Brings in the full exam-marker HTTP API on /api/exam (as-user RLS, E1/E2 fixes):
- S4-5 template CRUD (hybrid PUT + PATCH)
- S4-6 batches/scans/marks/results/CSV (A7), roster-from-class_students
- S4-7 Neo4j projection on save + neo4j-sync
Also fixes pre-existing E7: storage.py brace-doubling crash (all uploads).
Verified: 35 unit tests; live as-user RLS smoke .94 (templates 17/17, batches
20/20); live graph smoke .94+.209 (projection 17/17). Reviewed; data-loss guard
added (409 on destructive template PUT once marks recorded).
Co-Authored-By: Claude Opus 4.8 <[email protected]>
