fix(mcp): wrap websocket activity broadcasts in JSON-RPC notifications

Fixes a critical bug where the Antigravity MCP client would crash with 'invalid message version tag' during long-running tool executions. The server was broadcasting raw JSON activity objects ({'type': 'activity', 'data': ...}) over the WebSocket connection without wrapping them in the required JSON-RPC 2.0 Notification envelope, violating the protocol expectation on the proxy stub.

server/src/search.rs

@@ -10,6 +10,7 @@ pub struct MemoryIndex {
     index: Index,
     reader: IndexReader,
     writer: Arc<Mutex<IndexWriter>>,
+    needs_commit: Arc<std::sync::atomic::AtomicBool>,
 
     // Schema fields
     pub id_field: Field,
@@ -47,6 +48,7 @@ impl MemoryIndex {
             index,
             reader,
             writer: Arc::new(Mutex::new(writer)),
+            needs_commit: Arc::new(std::sync::atomic::AtomicBool::new(false)),
             id_field,
             title_field,
             body_field,
@@ -59,6 +61,7 @@ impl MemoryIndex {
         let writer = Arc::clone(&self.writer);
         let id_field = self.id_field;
         let id_val = e.name.clone();
+        let needs_commit = Arc::clone(&self.needs_commit);
         
         let doc = doc!(
             self.id_field => e.name.as_str(),
@@ -72,6 +75,7 @@ impl MemoryIndex {
             let writer = writer.lock().unwrap_or_else(|e| e.into_inner());
             writer.delete_term(tantivy::Term::from_field_text(id_field, &id_val));
             writer.add_document(doc)?;
+            needs_commit.store(true, std::sync::atomic::Ordering::SeqCst);
             Ok(())
         })
     }
@@ -80,6 +84,7 @@ impl MemoryIndex {
         let writer = Arc::clone(&self.writer);
         let id_field = self.id_field;
         let id_val = t.id.clone();
+        let needs_commit = Arc::clone(&self.needs_commit);
 
         let doc = doc!(
             self.id_field => t.id.as_str(),
@@ -93,6 +98,7 @@ impl MemoryIndex {
             let writer = writer.lock().unwrap_or_else(|e| e.into_inner());
             writer.delete_term(tantivy::Term::from_field_text(id_field, &id_val));
             writer.add_document(doc)?;
+            needs_commit.store(true, std::sync::atomic::Ordering::SeqCst);
             Ok(())
         })
     }
@@ -101,19 +107,24 @@ impl MemoryIndex {
         let writer = Arc::clone(&self.writer);
         let id_field = self.id_field;
         let id_val = id.to_string();
+        let needs_commit = Arc::clone(&self.needs_commit);
         
         tokio::task::spawn_blocking(move || {
             let writer = writer.lock().unwrap_or_else(|e| e.into_inner());
             writer.delete_term(tantivy::Term::from_field_text(id_field, &id_val));
+            needs_commit.store(true, std::sync::atomic::Ordering::SeqCst);
             Ok(())
         })
     }
 
     pub async fn commit(&self) -> tantivy::Result<()> {
         let writer = Arc::clone(&self.writer);
+        let needs_commit = Arc::clone(&self.needs_commit);
         tokio::task::spawn_blocking(move || {
-            let mut writer = writer.lock().unwrap_or_else(|e| e.into_inner());
-            writer.commit()?;
+            if needs_commit.swap(false, std::sync::atomic::Ordering::SeqCst) {
+                let mut writer = writer.lock().unwrap_or_else(|e| e.into_inner());
+                writer.commit()?;
+            }
             Ok(())
         })
         .await
@@ -182,6 +193,7 @@ impl MemoryIndex {
         let writer = Arc::clone(&self.writer);
         let id_field = self.id_field;
         let id_val = s.name.clone();
+        let needs_commit = Arc::clone(&self.needs_commit);
 
         let doc = doc!(
             self.id_field => s.name.as_str(),
@@ -195,6 +207,7 @@ impl MemoryIndex {
             let writer = writer.lock().unwrap_or_else(|e| e.into_inner());
             writer.delete_term(tantivy::Term::from_field_text(id_field, &id_val));
             writer.add_document(doc)?;
+            needs_commit.store(true, std::sync::atomic::Ordering::SeqCst);
             Ok(())
         })
     }
@@ -203,6 +216,7 @@ impl MemoryIndex {
         let writer = Arc::clone(&self.writer);
         let id_field = self.id_field;
         let id_val = a.id.clone();
+        let needs_commit = Arc::clone(&self.needs_commit);
 
         let doc = doc!(
             self.id_field => a.id.as_str(),
@@ -216,6 +230,7 @@ impl MemoryIndex {
             let writer = writer.lock().unwrap_or_else(|e| e.into_inner());
             writer.delete_term(tantivy::Term::from_field_text(id_field, &id_val));
             writer.add_document(doc)?;
+            needs_commit.store(true, std::sync::atomic::Ordering::SeqCst);
             Ok(())
         })
     }