fix(2meet-data-optimizer): stop auto-activating entity bridge on install

- 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

tests/unit/HookBusBridgeTest.php

@@ -18,9 +18,9 @@ class HookBusBridgeTest extends TestCase {
 
 	// ── is_enabled() ────────────────────────────────────────────────────────
 
-	public function test_is_enabled_default_true(): void {
-		// v2.5.4: Hook Bus is ON by default; option not set → true.
-		$this->assertTrue( WPDO_Hook_Bus_Bridge::is_enabled() );
+	public function test_is_enabled_default_false(): void {
+		// Hook Bus is opt-in; option not set → false. Existing sites store '1' explicitly.
+		$this->assertFalse( WPDO_Hook_Bus_Bridge::is_enabled() );
 	}
 
 	public function test_is_enabled_when_option_set_to_string_one(): void {