fix(wechat): defer 45047/45015 delivery and control customer message budget

Persist formal replies when WeChat customer-service quota is exhausted,
claim them once on the next passive response, skip progress notices for
page generation, and suppress failure notices while a formal reply is pending.

Co-authored-by: Cursor <cursoragent@cursor.com>

schema.sql

@@ -1010,6 +1010,20 @@ CREATE TABLE IF NOT EXISTS h5_wechat_mp_message_details (
   CONSTRAINT fk_wechat_mp_message_details_user FOREIGN KEY (user_id) REFERENCES h5_users(id) ON DELETE SET NULL
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
+CREATE TABLE IF NOT EXISTS h5_wechat_mp_deferred_delivery (
+  app_id VARCHAR(32) NOT NULL,
+  openid VARCHAR(64) NOT NULL,
+  priority TINYINT NOT NULL DEFAULT 10,
+  kind VARCHAR(32) NOT NULL DEFAULT 'text',
+  content MEDIUMTEXT NOT NULL,
+  metadata JSON NULL,
+  source_msg_id VARCHAR(128) NULL,
+  created_at BIGINT NOT NULL,
+  updated_at BIGINT NOT NULL,
+  PRIMARY KEY (app_id, openid),
+  KEY idx_wechat_deferred_updated (updated_at)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 CREATE TABLE IF NOT EXISTS h5_schedule_items (
   id CHAR(36) PRIMARY KEY,
   user_id CHAR(36) NOT NULL,