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/workers/ai_reindex.rs

@@ -0,0 +1,55 @@
+use loco_rs::prelude::*;
+use serde::{Deserialize, Serialize};
+
+use crate::services::{ai, worker_jobs};
+
+pub struct AiReindexWorker {
+    pub ctx: AppContext,
+}
+
+#[derive(Clone, Debug, Default, Deserialize, Serialize)]
+pub struct AiReindexWorkerArgs {
+    #[serde(default)]
+    pub job_id: Option<i32>,
+}
+
+#[async_trait]
+impl BackgroundWorker<AiReindexWorkerArgs> for AiReindexWorker {
+    fn build(ctx: &AppContext) -> Self {
+        Self { ctx: ctx.clone() }
+    }
+
+    fn tags() -> Vec<String> {
+        vec!["ai".to_string(), "reindex".to_string()]
+    }
+
+    async fn perform(&self, args: AiReindexWorkerArgs) -> Result<()> {
+        if let Some(job_id) = args.job_id {
+            if !worker_jobs::begin_job_execution(&self.ctx, job_id).await? {
+                return Ok(());
+            }
+
+            match ai::rebuild_index(&self.ctx).await {
+                Ok(summary) => {
+                    worker_jobs::mark_job_succeeded(
+                        &self.ctx,
+                        job_id,
+                        Some(serde_json::json!({
+                            "indexed_chunks": summary.indexed_chunks,
+                            "last_indexed_at": summary.last_indexed_at.map(|value| value.to_rfc3339()),
+                        })),
+                    )
+                    .await?;
+                    Ok(())
+                }
+                Err(error) => {
+                    worker_jobs::mark_job_failed(&self.ctx, job_id, error.to_string()).await?;
+                    Err(error)
+                }
+            }
+        } else {
+            ai::rebuild_index(&self.ctx).await?;
+            Ok(())
+        }
+    }
+}