fix(todo): Refetch session after TodoWrite tool completes

Problem: Todo tool updates database but client's currentSession.todos
remains stale, causing TodoList UI to show no todos.

Root cause: Todo tool only returns summary (not actual todos), and there's
no mechanism to update client state after database update.

Solution: Refetch session from server when TodoWrite tool completes.

Changes:
1. toolHandlers.ts: Added refetch logic in handleToolResult()
   - Detects when TodoWrite tool completes
   - Calls refetchCurrentSession() to fetch fresh data
2. Created refetch-session.ts utility
   - Fetches session from server via tRPC
   - Updates currentSession signal with fresh data
   - TodoList component re-renders with new todos

Flow:
- LLM calls TodoWrite tool
- Tool updates database
- Tool returns summary result
- handleToolResult detects TodoWrite completion
- refetchCurrentSession fetches session from server
- currentSession signal updated with fresh todos
- TodoList component shows todos

Result: Todo UI now displays after tool execution

Author: shtse8

packages/code/src/screens/chat/streaming/handlers/toolHandlers.ts

@@ -205,6 +205,15 @@ export function handleToolResult(
 			),
 		false, // Don't skip for completed - result updates are idempotent
 	);
+
+	// Refetch session if TodoWrite tool completed (todos were updated in database)
+	if (event.toolName === "TodoWrite" && currentSessionId) {
+		import("../../../utils/refetch-session.js").then(({ refetchCurrentSession }) => {
+			refetchCurrentSession(currentSessionId).catch((err) => {
+				console.error("[handleToolResult] Failed to refetch session after TodoWrite:", err);
+			});
+		});
+	}
 }
 
 export function handleToolError(

packages/code/src/utils/refetch-session.ts

@@ -0,0 +1,22 @@
+/**
+ * Session Refetch Utility
+ * Refetches session from server and updates client state
+ */
+
+import { getTRPCClient } from "@sylphx/code-client";
+import { updateCurrentSession } from "@sylphx/code-client";
+
+/**
+ * Refetch current session from server and update local state
+ * Used when session data changes on server (e.g., todos updated by tool)
+ */
+export async function refetchCurrentSession(sessionId: string): Promise<void> {
+	const client = getTRPCClient();
+
+	// @ts-expect-error - tRPC router types not fully resolved
+	const session = await client.session.getById.query({ sessionId });
+
+	if (session) {
+		updateCurrentSession(session);
+	}
+}