Add video download failure reporting feature

- Introduced a new API endpoint `POST /api/v1/video/remove_watermark/report_failure` for reporting download failures.
- Added a new database table `video_download_failures` to store details about failed downloads, including domain, URL, error message, and reporting metadata.
- Updated the video handler to process failure reports and save them to the database.
- Enhanced documentation to include details about the new reporting feature and its usage.

docs/sql/remove_watermark.sql

@@ -31,3 +31,19 @@ CREATE TABLE IF NOT EXISTS `video_parse_unlocks` (
   PRIMARY KEY (`id`),
   UNIQUE KEY `uniq_video_unlock_date` (`mini_program_id`,`user_id`,`unlock_date`)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+-- 下载失败上报
+CREATE TABLE IF NOT EXISTS `video_download_failures` (
+  `id` bigint unsigned NOT NULL AUTO_INCREMENT,
+  `created_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  `updated_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  `deleted_at` datetime DEFAULT NULL,
+  `domain` varchar(255) DEFAULT NULL,
+  `failed_url` varchar(1000) NOT NULL,
+  `error_message` text,
+  `reported_at` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  `user_agent` varchar(255) DEFAULT NULL,
+  `client_ip` varchar(64) DEFAULT NULL,
+  PRIMARY KEY (`id`),
+  KEY `idx_video_download_domain` (`domain`,`reported_at`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;