spike: fetch Room TBA classes and parse schedule slots (Phase 0)

[smmariquit]

Plan: docs/IMPLEMENTATION_PLAN.md §6 Phase 0

Goal

Prove we can load a full term from Room TBA and parse ≥95% of LEC/LAB schedule strings into grid blocks.

Tasks

• room-tba-client stub: GET /api/terms, GET /api/classes?term_id=
• Decide CORS vs server proxy (see ROOM_TBA_INTEGRATION.md)
• Port slot parser rules from Room TBA schedule-import/day-stops
• Log parse failures with raw schedule string for fixture collection

Definition of done

• Script or dev page processes current-term class export from staging/production
• 20+ unit test vectors for Th, MWF, MTWTHFS, etc.

Cross-repo

• File room-tba issue for CORS on /api/classes and /api/terms if browser fetch blocked