fix: address review feedback (星月)

1. trySendSync: wrap child.send in try/catch — IPC race between connected check and send
2. gracefulStop: same try/catch for shutdown send
3. Remove crashTimestamps reset on ready — crash window detection was being bypassed

packages/daemon/src/worker-runtime.ts

@@ -187,7 +187,6 @@ export function createWorkerRuntime<K extends string>(
     if (isReadyIpcMessage(msg)) {
       if (slot.state === "starting") {
         slot.state = "ready";
-        slot.crashTimestamps = [];
         config.onReady(slot.key, msg);
         resolveReadyWaiters(slot);
       }
@@ -272,7 +271,11 @@ export function createWorkerRuntime<K extends string>(
     slot.expectExit = true;
     slot.state = "draining";
     const child = slot.child;
-    child.send({ type: "shutdown" });
+    try {
+      child.send({ type: "shutdown" });
+    } catch {
+      // IPC channel may have closed between null-check and send
+    }
     await waitForChildExit(child, config.shutdownTimeoutMs);
   }
 
@@ -330,8 +333,12 @@ export function createWorkerRuntime<K extends string>(
       if (child === null || !child.connected) {
         return false;
       }
-      child.send(msg as Serializable);
-      return true;
+      try {
+        child.send(msg as Serializable);
+        return true;
+      } catch {
+        return false;
+      }
     },
 
     start: async (key: K) => {