Add set_output tool (#205)

entry.ts

@@ -15,6 +15,10 @@ async function run(): Promise<void> {
     if (!result.success) {
       throw new Error(result.error || "Agent execution failed");
     }
+
+    if (result.result) {
+      core.setOutput("result", result.result);
+    }
   } catch (error) {
     const errorMessage = error instanceof Error ? error.message : "Unknown error occurred";
     core.setFailed(`Action failed: ${errorMessage}`);