feat(chat): enhance resumeStream handling to manage transient status during stream resumption

apps/desktop/layer/renderer/src/modules/ai-chat/store/chat-core/chat-instance.ts

@@ -17,6 +17,17 @@ export class ZustandChat extends AbstractChat<BizUIMessage> {
     const state = new ZustandChatState(messages, updateZustandState, init.id || "")
     super({ ...init, state })
     this.state = state
+
+    const baseResumeStream = this.resumeStream.bind(this)
+    // Track resume calls so the state can ignore the temporary "submitted" status when no stream exists.
+    this.resumeStream = async (...args) => {
+      this.state.setResumingStream(true)
+      try {
+        return await baseResumeStream(...args)
+      } finally {
+        this.state.setResumingStream(false)
+      }
+    }
   }
 
   // Public getter for state access

apps/desktop/layer/renderer/src/modules/ai-chat/store/chat-core/chat-state.ts

@@ -15,6 +15,7 @@ export class ZustandChatState implements ChatState<BizUIMessage> {
   #status: ChatStatus = "ready"
   #error: Error | undefined = undefined
   #eventEmitter = new ChatStateEventEmitter()
+  #isResumingStream = false
 
   constructor(
     initialMessages: BizUIMessage[] = [],
@@ -61,12 +62,24 @@ export class ZustandChatState implements ChatState<BizUIMessage> {
     })
 
     this.#eventEmitter.on("status", ({ status }) => {
+      // Suppress the transient "submitted" status emitted when resumeStream probes for an active stream.
+      if (this.#isResumingStream && status === "submitted") {
+        return
+      }
+
       this.updateZustandState((state) => {
         const isStreaming = status === "streaming"
         if (isStreaming) {
           void state.chatActions.markSessionSynced()
         }
 
+        if (
+          this.#isResumingStream &&
+          (status === "ready" || status === "streaming" || status === "error")
+        ) {
+          this.#isResumingStream = false
+        }
+
         return {
           ...state,
           status,
@@ -185,4 +198,8 @@ export class ZustandChatState implements ChatState<BizUIMessage> {
   destroy(): void {
     this.#eventEmitter.clear()
   }
+
+  setResumingStream(isResuming: boolean) {
+    this.#isResumingStream = isResuming
+  }
 }