refactor(zones): 回填 Zone_Router + Routing_Predicate（PR-C）

A v3.0.1/v3.4.0 的架構深化，B 完全缺席：

新增
- includes/zones/class-tmdo-zone-router.php：module_name / read / write /
  delete_field / delete_post 五個 static 分派點
- includes/class-tmdo-routing-predicate.php：entity_bridge_owns（含
  request-level cache，B 原本沒有）+ should_{write,read,query}_from_zone
  + flush_cache

改寫
- Sync_Bridge 改用兩者，移除 5 個 private wrapper（get_zone_module /
  read_from_zone / write_to_zone / delete_from_zone / is_owned_by_entity_bridge）
  與 44 行 inline cleanup_post → Zone_Router::delete_post 一行（400→269 行）
- Query_Router 抽出 extract_hot_clauses() public static，pre_get_posts 變薄殼
- 收斂 5 處重複的 'hot_'/'cold_' . sanitize_key()（rest-api ×3、
  hot/cold-migration ×2）
- back-compat 補 WPDO_Zone_Router / WPDO_Routing_Predicate alias

測試
- 移植 ZoneRouterTest（250 行）+ RoutingPredicateTest（85 行）
- SyncBridgeEntityGuardTest 的 setUp/tearDownAfterClass 補 flush_cache()，
  否則 entity_bridge_cache 會跨測試污染（A v3.4.6 踩過同一個坑）

unit 409 / integration 398 GREEN

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TbG1keQQ7XBa7qMQY16KCY

includes/query/class-tmdo-query-router.php

@@ -2,7 +2,7 @@
 /**
  * Zone A Query Router for flat-column hot table rewrites.
  *
- * @package WP_Data_Optimizer
+ * @package TMDO
  */
 
 if ( ! defined( 'ABSPATH' ) ) {
@@ -47,6 +47,53 @@ class TMDO_Query_Router {
 	/**
 	 * Extract meta_query clauses that can be served by hot tables.
 	 *
+	 * Separated from the hook callback so it can be called and asserted directly
+	 * in unit tests without triggering a full WP_Query lifecycle.
+	 *
+	 * @param array    $raw_meta_query Raw meta_query array from WP_Query.
+	 * @param string[] $post_types     Post types being queried.
+	 * @return array{hot_clauses: array<string, list<array>>, remaining: array} Extracted and leftover clauses.
+	 */
+	public static function extract_hot_clauses( array $raw_meta_query, array $post_types ): array {
+		$registry    = TMDO_Schema_Registry::instance();
+		$hot_clauses = array();
+		$remaining   = array();
+
+		foreach ( $raw_meta_query as $k => $clause ) {
+			if ( 'relation' === $k || ! is_array( $clause ) || ! isset( $clause['key'] ) ) {
+				$remaining[ $k ] = $clause;
+				continue;
+			}
+
+			$matched = false;
+			foreach ( $post_types as $pt ) {
+				$field = $registry->get_field( $pt, $clause['key'] );
+				if ( $field && 'hot' === $field['zone'] && TMDO_Routing_Predicate::should_query_from_zone( $pt, 'hot' ) ) {
+					$hot_clauses[ $pt ][] = array(
+						'column'  => $field['column'],
+						'value'   => $clause['value'] ?? '',
+						'compare' => strtoupper( trim( $clause['compare'] ?? '=' ) ),
+						'type'    => strtoupper( trim( $clause['type'] ?? 'CHAR' ) ),
+					);
+					$matched              = true;
+					break;
+				}
+			}
+
+			if ( ! $matched ) {
+				$remaining[ $k ] = $clause;
+			}
+		}
+
+		return array(
+			'hot_clauses' => $hot_clauses,
+			'remaining'   => $remaining,
+		);
+	}
+
+	/**
+	 * Detect hot-table clauses in meta_query and stash them for later hooks.
+	 *
 	 * @param \WP_Query $query The WP_Query object.
 	 * @return void
 	 */
@@ -65,53 +112,19 @@ class TMDO_Query_Router {
 			return;
 		}
 
-		$registry    = TMDO_Schema_Registry::instance();
-		$hot_clauses = array(); // Keyed by post_type.
-		$remaining   = array();
+		$result = self::extract_hot_clauses( $raw_meta_query, $post_types );
 
-		foreach ( $raw_meta_query as $k => $clause ) {
-			if ( 'relation' === $k || ! is_array( $clause ) || ! isset( $clause['key'] ) ) {
-				$remaining[ $k ] = $clause;
-				continue;
-			}
-
-			$matched = false;
-			foreach ( $post_types as $pt ) {
-				$field = $registry->get_field( $pt, $clause['key'] );
-				if ( $field && 'hot' === $field['zone'] ) {
-					// Check module is query-active.
-					$module = 'hot_' . sanitize_key( $pt );
-					if ( ! TMDO_Feature_Flags::is_query_active( $module ) ) {
-						continue;
-					}
-
-					$hot_clauses[ $pt ][] = array(
-						'column'  => $field['column'],
-						'value'   => $clause['value'] ?? '',
-						'compare' => strtoupper( trim( $clause['compare'] ?? '=' ) ),
-						'type'    => strtoupper( trim( $clause['type'] ?? 'CHAR' ) ),
-					);
-					$matched              = true;
-					break;
-				}
-			}
-
-			if ( ! $matched ) {
-				$remaining[ $k ] = $clause;
-			}
-		}
-
-		if ( empty( $hot_clauses ) ) {
+		if ( empty( $result['hot_clauses'] ) ) {
 			return;
 		}
 
-		// Preserve relation if there are remaining clauses.
+		$remaining = $result['remaining'];
 		if ( isset( $raw_meta_query['relation'] ) && ! isset( $remaining['relation'] ) ) {
 			$remaining['relation'] = $raw_meta_query['relation'];
 		}
 
 		$query->set( 'meta_query', $remaining );
-		$query->set( self::QUERY_VAR, $hot_clauses );
+		$query->set( self::QUERY_VAR, $result['hot_clauses'] );
 	}
 
 	/**