perf: replace inefficient memory cloning vectors with fast zero-allocation read iterators

server/src/handlers_v2/notes.rs

@@ -51,7 +51,7 @@ impl McpTool for ReadStickyNotesHandler {
     }
 
     async fn execute(&self, _args: Value, state: Arc<MemoryState>) -> Result<String, String> {
-        let data = serde_json::to_string(&state.sticky.read()).unwrap_or_else(|_| "[]".to_string());
+        let data = state.sticky.read_with(|s| serde_json::to_string(s).unwrap_or_else(|_| "[]".to_string()));
         Ok(data.to_string())
     }
 }
@@ -161,11 +161,16 @@ impl McpTool for ReadHandoffMemosHandler {
 
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> Result<String, String> {
         let req: ReadHandoffMemosTool = serde_json::from_value(args).map_err(|e| e.to_string())?;
-        let mut items = state.handoff_memos.read();
-        if let Some(ns) = req.namespace {
-            items.retain(|i| i.namespace == ns);
-        }
-        let data = serde_json::to_string(&items).unwrap_or_default();
+        let data = state.handoff_memos.read_with(|items| {
+            let filtered: Vec<_> = items.iter().filter(|i| {
+                if let Some(ns) = &req.namespace {
+                    &i.namespace == ns
+                } else {
+                    true
+                }
+            }).collect();
+            serde_json::to_string(&filtered).unwrap_or_default()
+        });
         Ok(data.to_string())
     }
 }
@@ -271,3 +276,4 @@ impl McpTool for GenerateStandupReportHandler {
         Ok(report.to_string())
     }
 }
+