fix(2meet-data-optimizer): default misc bucket and garbage filter to off

- Both term/comment filters now default to disabled for new installs, so
  activating the plugin no longer reroutes or drops other plugins' meta
- One-time maybe_upgrade() migration keeps the misc bucket on for sites
  that already hold misc rows and never set the toggle (data stays readable)
- Admin toggles show the same defaults as the filters

Verify: phpunit-integration --filter 'defaults_false|preserve_default';
  unit 600 OK, integration 420 OK
PR: PR-006

includes/class-tmdo-installer.php

@@ -40,6 +40,9 @@ class TMDO_Installer {
 	 */
 	private const SCHEMA_VERSION = '2.1.0';
 
+	/** Set once maybe_preserve_misc_bucket_default() has run for this site. */
+	public const MISC_BUCKET_DEFAULT_FLAG = 'wpdo_misc_bucket_default_v2';
+
 	/** Allowed SQL base types for hot-zone column definitions. */
 	private const ALLOWED_COL_BASE_TYPES = array(
 		'bigint',
@@ -299,6 +302,34 @@ class TMDO_Installer {
 		if ( get_option( 'wpdo_db_version' ) !== self::SCHEMA_VERSION ) {
 			self::install();
 		}
+		self::maybe_preserve_misc_bucket_default();
+	}
+
+	/**
+	 * One-time migration for the misc bucket default flip (on → off).
+	 *
+	 * The bucket used to default to enabled; its rows are only readable while it
+	 * is on. Sites that already hold misc rows and never set the toggle get '1'
+	 * persisted so turning the default off cannot hide their data. Runs from
+	 * maybe_upgrade() rather than install() because install() only runs when
+	 * SCHEMA_VERSION changes; the flag is autoloaded since it is read per request.
+	 *
+	 * @return void
+	 */
+	public static function maybe_preserve_misc_bucket_default(): void {
+		if ( get_option( self::MISC_BUCKET_DEFAULT_FLAG ) || ! class_exists( 'TMDO_Term_Comment_Misc_Bucket' ) ) {
+			return;
+		}
+
+		$unset    = false === get_option( TMDO_Term_Comment_Misc_Bucket::OPT_ENABLED );
+		$has_rows = TMDO_Term_Comment_Misc_Bucket::count_rows( 'term' ) > 0
+			|| TMDO_Term_Comment_Misc_Bucket::count_rows( 'comment' ) > 0;
+
+		if ( $unset && $has_rows ) {
+			update_option( TMDO_Term_Comment_Misc_Bucket::OPT_ENABLED, '1', false );
+		}
+
+		update_option( self::MISC_BUCKET_DEFAULT_FLAG, '1', true );
 	}
 
 	// ── v2.0.0 entity + audit + shadow_diffs schema (PR-2) ─────────────────

includes/integrations/class-tmdo-term-comment-garbage-filter.php

@@ -109,12 +109,12 @@ final class TMDO_Term_Comment_Garbage_Filter {
 	}
 
 	/**
-	 * Check the admin toggle. Defaults to enabled.
+	 * Check the admin toggle. Defaults to disabled.
 	 *
 	 * @return bool
 	 */
 	public static function is_enabled(): bool {
-		return (bool) get_option( self::OPT_ENABLED, '1' );
+		return (bool) get_option( self::OPT_ENABLED, '0' );
 	}
 
 	/**

includes/integrations/class-tmdo-term-comment-misc-bucket.php

@@ -95,12 +95,13 @@ final class TMDO_Term_Comment_Misc_Bucket {
 	}
 
 	/**
-	 * Check the admin toggle. Defaults to enabled.
+	 * Check the admin toggle. Defaults to disabled; sites that already hold misc
+	 * rows keep it on via TMDO_Installer::maybe_preserve_misc_bucket_default().
 	 *
 	 * @return bool
 	 */
 	public static function is_enabled(): bool {
-		return (bool) get_option( self::OPT_ENABLED, '1' );
+		return (bool) get_option( self::OPT_ENABLED, '0' );
 	}
 
 	/**