MARS-672: author get_practica_detail_bundle DB function

Author get_practica_detail_bundle(practicaId) DB function (changelog/reviews/comentarios as JSON sets, get_exam_matrix_bundle shape from mig 083) for mi-cursada/[id]/page.tsx:68's 4-wide fan-out. Part of MARS-672 pool-exhaustion fix. Layout.tsx:34 scalar bundle blocked on coder clarifying getProfilePhotoNagState's role/view-as inputs.