- install() no longer switches the Hook Bus on or puts user/term/comment
into dual_write; the now-unused maybe_autoactivate_entity_bridge() is gone
- Hook Bus and Mode_Manager defaults are off/disabled; sites with stored
modes (incl. aeav_only) keep them since only unset keys use defaults
- Guard run_dbdelta()'s upgrade.php require like install_v2_tables() so
install() can run under the integration test stub
Verify: InstallerV2Test::test_install_does_not_enable_entity_bridge,
ModeManagerDefaultsTest; unit 602 OK, integration 421 OK
PR: PR-007