vPracticaHistorial conducto-leg predicate pushdown (dbperf mig067)

dbperf snapshot flagged vPracticaHistorial: 328 calls, mean=150ms, +49201ms total. Root cause (db-mars-cc EXPLAIN ANALYZE): practicaToothConductosArchive has no practicaId column — view joined ALL conductos to ALL practicaTeeth then filtered practicaId via COALESCE AFTER the join (planner can't push predicate through COALESCE); conducto leg was 96% of shared buffers (7143/7457). Fix (db02, view owner, Class-A view rewrite): filter teeth by practicaId first using existing indexes, then index-lookup conductos by practicaToothId — zero new DDL, existing indexes only. Migration 067, SHA 022218a. EXPLAIN 7457->358 buffers (~21x). Audit design-GO'd pre-apply.