feat: 添加 AI 索引重建功能，优化相关 API 和工作流，增强内存管理配置

backend/src/services/worker_jobs.rs

@@ -11,6 +11,7 @@ use crate::{
     models::_entities::{notification_deliveries, worker_jobs},
     services::subscriptions,
     workers::{
+        ai_reindex::{AiReindexWorker, AiReindexWorkerArgs},
         downloader::{DownloadWorker, DownloadWorkerArgs},
         notification_delivery::{NotificationDeliveryWorker, NotificationDeliveryWorkerArgs},
     },
@@ -27,6 +28,7 @@ pub const JOB_STATUS_CANCELLED: &str = "cancelled";
 
 pub const WORKER_DOWNLOAD_MEDIA: &str = "worker.download_media";
 pub const WORKER_NOTIFICATION_DELIVERY: &str = "worker.notification_delivery";
+pub const WORKER_AI_REINDEX: &str = "worker.ai_reindex";
 pub const TASK_RETRY_DELIVERIES: &str = "task.retry_deliveries";
 pub const TASK_SEND_WEEKLY_DIGEST: &str = "task.send_weekly_digest";
 pub const TASK_SEND_MONTHLY_DIGEST: &str = "task.send_monthly_digest";
@@ -164,6 +166,7 @@ fn trim_to_option(value: Option<String>) -> Option<String> {
 
 fn queue_name_for(worker_name: &str) -> Option<String> {
     match worker_name {
+        WORKER_AI_REINDEX => Some("ai".to_string()),
         WORKER_DOWNLOAD_MEDIA => Some("media".to_string()),
         WORKER_NOTIFICATION_DELIVERY => Some("notifications".to_string()),
         TASK_RETRY_DELIVERIES => Some("maintenance".to_string()),
@@ -174,6 +177,7 @@ fn queue_name_for(worker_name: &str) -> Option<String> {
 
 fn label_for(worker_name: &str) -> String {
     match worker_name {
+        WORKER_AI_REINDEX => "AI 索引重建".to_string(),
         WORKER_DOWNLOAD_MEDIA => "远程媒体下载".to_string(),
         WORKER_NOTIFICATION_DELIVERY => "通知投递".to_string(),
         TASK_RETRY_DELIVERIES => "重试待投递通知".to_string(),
@@ -185,6 +189,8 @@ fn label_for(worker_name: &str) -> String {
 
 fn description_for(worker_name: &str) -> String {
     match worker_name {
+        WORKER_AI_REINDEX => "按当前站点内容重新生成 AI 检索索引，并分批写入向量数据。"
+            .to_string(),
         WORKER_DOWNLOAD_MEDIA => "抓取远程图片 / PDF 到媒体库，并回写媒体元数据。".to_string(),
         WORKER_NOTIFICATION_DELIVERY => "执行订阅通知、测试通知与 digest 投递。".to_string(),
         TASK_RETRY_DELIVERIES => "扫描 retry_pending 的通知记录并重新入队。".to_string(),
@@ -196,6 +202,7 @@ fn description_for(worker_name: &str) -> String {
 
 fn tags_for(worker_name: &str) -> Value {
     match worker_name {
+        WORKER_AI_REINDEX => json!(["ai", "reindex"]),
         WORKER_DOWNLOAD_MEDIA => json!(["media", "download"]),
         WORKER_NOTIFICATION_DELIVERY => json!(["notifications", "delivery"]),
         TASK_RETRY_DELIVERIES => json!(["maintenance", "retry"]),
@@ -249,6 +256,7 @@ fn to_job_record(item: worker_jobs::Model) -> WorkerJobRecord {
 
 fn catalog_entries() -> Vec<WorkerCatalogEntry> {
     [
+        (WORKER_AI_REINDEX, JOB_KIND_WORKER, true, true),
         (WORKER_DOWNLOAD_MEDIA, JOB_KIND_WORKER, true, true),
         (WORKER_NOTIFICATION_DELIVERY, JOB_KIND_WORKER, true, true),
         (TASK_RETRY_DELIVERIES, JOB_KIND_TASK, true, true),
@@ -313,6 +321,13 @@ async fn dispatch_download(args_ctx: AppContext, args: DownloadWorkerArgs) {
     }
 }
 
+async fn dispatch_ai_reindex(args_ctx: AppContext, args: AiReindexWorkerArgs) {
+    let worker = AiReindexWorker::build(&args_ctx);
+    if let Err(error) = worker.perform(args).await {
+        tracing::warn!("ai reindex worker execution failed: {error}");
+    }
+}
+
 async fn dispatch_notification_delivery(
     args_ctx: AppContext,
     args: NotificationDeliveryWorkerArgs,
@@ -340,6 +355,21 @@ async fn enqueue_download_worker(ctx: &AppContext, args: DownloadWorkerArgs) ->
     }
 }
 
+async fn enqueue_ai_reindex_worker(ctx: &AppContext, args: AiReindexWorkerArgs) -> Result<()> {
+    match AiReindexWorker::perform_later(ctx, args.clone()).await {
+        Ok(_) => Ok(()),
+        Err(Error::QueueProviderMissing) => {
+            tokio::spawn(dispatch_ai_reindex(ctx.clone(), args));
+            Ok(())
+        }
+        Err(error) => {
+            tracing::warn!("ai reindex worker queue unavailable, falling back to local task: {error}");
+            tokio::spawn(dispatch_ai_reindex(ctx.clone(), args));
+            Ok(())
+        }
+    }
+}
+
 async fn enqueue_notification_worker(
     ctx: &AppContext,
     args: NotificationDeliveryWorkerArgs,
@@ -717,6 +747,46 @@ pub async fn queue_notification_delivery_job(
     get_job_record(ctx, job.id).await
 }
 
+pub async fn queue_ai_reindex_job(
+    ctx: &AppContext,
+    requested_by: Option<String>,
+    requested_source: Option<String>,
+    parent_job_id: Option<i32>,
+    trigger_mode: Option<String>,
+) -> Result<WorkerJobRecord> {
+    let base_args = AiReindexWorkerArgs { job_id: None };
+    let payload = serde_json::to_value(&base_args)?;
+
+    let job = create_job(
+        ctx,
+        CreateWorkerJobInput {
+            parent_job_id,
+            job_kind: JOB_KIND_WORKER.to_string(),
+            worker_name: WORKER_AI_REINDEX.to_string(),
+            display_name: Some("重建 AI 索引".to_string()),
+            queue_name: queue_name_for(WORKER_AI_REINDEX),
+            requested_by,
+            requested_source,
+            trigger_mode,
+            payload: Some(payload),
+            tags: Some(tags_for(WORKER_AI_REINDEX)),
+            related_entity_type: Some("ai_index".to_string()),
+            related_entity_id: Some("site".to_string()),
+            max_attempts: 1,
+        },
+    )
+    .await?;
+
+    enqueue_ai_reindex_worker(
+        ctx,
+        AiReindexWorkerArgs {
+            job_id: Some(job.id),
+        },
+    )
+    .await?;
+    get_job_record(ctx, job.id).await
+}
+
 pub async fn spawn_retry_deliveries_task(
     ctx: &AppContext,
     limit: Option<u64>,
@@ -810,6 +880,17 @@ pub async fn retry_job(
     let payload = item.payload.clone().unwrap_or(Value::Null);
 
     match item.worker_name.as_str() {
+        WORKER_AI_REINDEX => {
+            let _ = serde_json::from_value::<AiReindexWorkerArgs>(payload)?;
+            queue_ai_reindex_job(
+                ctx,
+                requested_by,
+                requested_source,
+                Some(item.id),
+                Some("retry".to_string()),
+            )
+            .await
+        }
         WORKER_DOWNLOAD_MEDIA => {
             let args = serde_json::from_value::<DownloadWorkerArgs>(payload)?;
             queue_download_job(