fix(search): prevent memory leaks and duplication in tantivy search index by explicitly deleting prior terms during updates and syncing store deletions

server/src/handlers_v2/tasks.rs

@@ -66,6 +66,7 @@ impl McpTool for DeleteTaskHandler {
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> Result<String, String> {
         let req: DeleteTaskTool = serde_json::from_value(args).map_err(|e| e.to_string())?;
         let mut deleted_count = 0;
+        let mut actually_deleted = Vec::new();
         state.tasks.modify(|tasks| {
             let initial_len = tasks.len();
             // Collect IDs of tasks to delete (this task + all its recursive children)
@@ -93,12 +94,17 @@ impl McpTool for DeleteTaskHandler {
                     queue.extend(children.iter().cloned());
                 }
             }
-
-            tasks.retain(|t| !to_delete.contains(&t.id));
+            
+            actually_deleted = to_delete.into_iter().collect();
+            tasks.retain(|t| !actually_deleted.contains(&t.id));
             deleted_count = initial_len - tasks.len();
         });
 
         if deleted_count > 0 {
+            let idx = state.search_index.read().unwrap_or_else(|e| e.into_inner()).clone();
+            for id in actually_deleted {
+                let _ = idx.delete_document(&id).await;
+            }
             Ok(vec![
                 format!("Deleted task and its children ({} total).", deleted_count).to_string(),
             ][0]