fix(2meet-data-optimizer): serialize arrays in text fields instead of storing "Array"

- TMDO_Type_Caster: text / textarea values that are arrays or objects are
  stored with maybe_serialize() (was (string) → the literal "Array", which
  bridge-restore-native then wrote back over native meta); from_db()
  unserializes them with TMDO_Safe_Unserialize. text columns are
  VARCHAR(255): longer values are stored NULL (native keeps them) and
  logged as text_overflow.
- Add `wp tmdo repair-array-literals [--entity] [--confirm]`
  (TMDO_Array_Literal_Repair): rewrites flat "Array" values from native
  meta and lists native rows that are "Array" themselves (backup needed).
- Verify: TypeCasterSerializeTest 13 OK, ArrayLiteralRepairTest 3 OK;
  unit 685 OK, integration 483 OK, phpcs (phpcs.xml) 0, stan OK;
  live `serialized` 3 PASS; dev36 repair dry-run lists the value corrupted
  by the 2026-09-26 round trip (user #1 community-events-location)
- PR: PR-055

includes/engine/class-tmdo-type-caster.php

@@ -70,10 +70,12 @@ final class TMDO_Type_Caster {
 				return $value;
 
 			case 'text':
-				return (string) $value;
+				return self::fit_text( is_scalar( $value ) ? (string) $value : maybe_serialize( $value ), $field_def );
 
 			case 'textarea':
-				return (string) $value;
+				// Arrays / objects are serialized like WP stores them in native meta;
+				// (string) would store the literal "Array".
+				return is_scalar( $value ) ? (string) $value : maybe_serialize( $value );
 
 			default:
 				// 未知型別：嘗試序列化（向後相容 WordPress get_metadata 行為）
@@ -81,6 +83,33 @@ final class TMDO_Type_Caster {
 		}
 	}
 
+	/** 'text' columns are VARCHAR(255) (TMDO_Schema_Manager type map). */
+	private const TEXT_MAX_CHARS = 255;
+
+	/**
+	 * Keep a text value only if it fits its VARCHAR(255) column; otherwise
+	 * store NULL (native meta keeps the full value) and log the overflow.
+	 *
+	 * @param string               $value     Value to store.
+	 * @param array<string, mixed> $field_def Field definition.
+	 * @return string|null
+	 */
+	private static function fit_text( string $value, array $field_def ): ?string {
+		$length = mb_strlen( $value );
+		if ( $length <= self::TEXT_MAX_CHARS ) {
+			return $value;
+		}
+		TMDO_Logger::warning(
+			'text_overflow',
+			array(
+				'group'  => $field_def['group'] ?? '',
+				'key'    => $field_def['key'] ?? '',
+				'length' => $length,
+			)
+		);
+		return null;
+	}
+
 	/**
 	 * DB → PHP 轉換（讀取）
 	 */
@@ -111,9 +140,12 @@ final class TMDO_Type_Caster {
 				return ( json_last_error() === JSON_ERROR_NONE ) ? $decoded : $value;
 
 			case 'enum':
+				return (string) $value;
+
 			case 'text':
 			case 'textarea':
-				return (string) $value;
+				// Arrays were stored serialized (to_db); plain strings pass through.
+				return TMDO_Safe_Unserialize::run( (string) $value );
 
 			default:
 				// v2.13.3: object-injection-safe unserialize (fixes L-DESER-1).