PR #173 fixed cad_buildings_pkey but missed 5 other indexes. Same root cause:
PG does NOT auto-rename indexes on table rename → all 6 backing indexes
remain on cad_buildings_old_apr26 with original names.
Add 5 more `ALTER INDEX IF EXISTS ... RENAME TO ..._old_apr26_*` statements
for: geom_gist, quarter_idx, objdoc_idx, complex_idx, purpose_idx.
Migration 92 still NOT in _schema_migrations (4× rollback now). Next deploy
will re-apply cleanly.
