vComisionAyudantesByJtp SA-join fix

Surfaced during db02-mars-cc's MARS-17 unused-view re-verification (2026-07-16): vComisionAyudantesByJtp needs an SA-join fix per db-efficiency-audit.md:67, not currently dead — excluded from the MARS-15/16/17 view-drop batch on that basis. Filing as its own tracked item since db02's assumed 'MARS-21/academic-core lane' reference was stale (MARS-21 is an unrelated, already-closed JTP live-vs-snapshot WI).