fix: proper tab isolation with updateTabById

- Added updateTabById function to store for updating specific tabs by ID
- Capture tab ID at request start (requestTabId)
- All streaming updates now go to the captured tab ID, not activeTabId
- Switching tabs during streaming no longer pollutes other tabs
- Local UI state only updates if still on the same tab
- Complete isolation: each tab's history/preview/agent is independent

components/AIAssist.tsx

@@ -418,6 +418,7 @@ export default function AIAssist() {
         addAIAssistTab,
         removeAIAssistTab,
         updateActiveTab,
+        updateTabById,
         selectedProvider,
         selectedModels,
         setSelectedModel
@@ -515,6 +516,10 @@ export default function AIAssist() {
         const finalInput = forcedPrompt || input;
         if (!finalInput.trim() || isProcessing) return;
 
+        // CRITICAL: Capture the tab ID at the start of this request
+        const requestTabId = activeTabId;
+        if (!requestTabId) return;
+
         const controller = new AbortController();
         setAbortController(controller);
 
@@ -526,7 +531,7 @@ export default function AIAssist() {
                 timestamp: new Date(),
             };
             const newHistory = [...aiAssistHistory, userMsg];
-            updateActiveTab({ history: newHistory });
+            updateTabById(requestTabId, { history: newHistory });
             setInput("");
         }
 
@@ -540,9 +545,10 @@ export default function AIAssist() {
             timestamp: new Date()
         };
 
-        // Update history in active tab
-        const updatedHistory = [...aiAssistHistory, assistantMsg];
-        updateActiveTab({ history: updatedHistory });
+        // Update history in the REQUEST's tab (not current active tab)
+        const startingHistory = [...aiAssistHistory, { role: "user" as const, content: finalInput, timestamp: new Date() }];
+        const updatedHistory = [...startingHistory, assistantMsg];
+        updateTabById(requestTabId, { history: updatedHistory });
 
         try {
             let accumulated = "";
@@ -571,22 +577,21 @@ export default function AIAssist() {
 
                         if (streamStatus) setStatus(streamStatus);
 
+                        // Only update local state if we're still on the same tab
+                        if (activeTabId === requestTabId) {
                             if (preview && JSON.stringify(preview) !== JSON.stringify(lastParsedPreview)) {
                                 setPreviewData(preview);
                                 lastParsedPreview = preview;
                                 setShowCanvas(true);
                                 if (isPreviewRenderable(preview)) setViewMode("preview");
-
-                            // Save preview data to tab
-                            updateActiveTab({ previewData: preview });
                             }
 
                             if (agent !== currentAgent) {
                                 setCurrentAgent(agent);
-                            updateActiveTab({ currentAgent: agent });
+                            }
                         }
 
-                        // Stream updates to current tab history
+                        // Always update the REQUEST's tab (by ID), not the active tab
                         const lastMsg = {
                             role: "assistant" as const,
                             content: accumulated,
@@ -595,8 +600,10 @@ export default function AIAssist() {
                             timestamp: new Date()
                         };
 
-                        updateActiveTab({
-                            history: [...updatedHistory.slice(0, -1), lastMsg]
+                        updateTabById(requestTabId, {
+                            history: [...updatedHistory.slice(0, -1), lastMsg],
+                            previewData: preview || undefined,
+                            currentAgent: agent
                         });
                     },
                     signal: controller.signal
@@ -617,7 +624,7 @@ export default function AIAssist() {
             console.error("Assist error:", error);
             const message = error instanceof Error ? error.message : "AI Assist failed";
             const errorMsg: AIAssistMessage = { role: "assistant", content: message, timestamp: new Date() };
-            updateActiveTab({ history: [...aiAssistHistory, errorMsg] });
+            updateTabById(requestTabId, { history: [...aiAssistHistory, errorMsg] });
         } finally {
             setIsProcessing(false);
             setAbortController(null);

lib/store.ts

@@ -56,6 +56,7 @@ interface AppState {
   addAIAssistTab: (agent?: string) => void;
   removeAIAssistTab: (id: string) => void;
   updateActiveTab: (updates: Partial<AIAssistTab>) => void;
+  updateTabById: (tabId: string, updates: Partial<AIAssistTab>) => void;
 
   setLanguage: (lang: "en" | "ru" | "he") => void;
   setSelectedProvider: (provider: ModelProvider) => void;
@@ -149,6 +150,11 @@ const useStore = create<AppState>((set) => ({
       t.id === state.activeTabId ? { ...t, ...updates } : t
     )
   })),
+  updateTabById: (tabId, updates) => set((state) => ({
+    aiAssistTabs: state.aiAssistTabs.map(t =>
+      t.id === tabId ? { ...t, ...updates } : t
+    )
+  })),
 
   setLanguage: (lang) => set({ language: lang }),
   setSelectedProvider: (provider) => set({ selectedProvider: provider }),