feat(chat): add activeTopicOrSession state to track current view

Add new state field and action to track whether the user is viewing topics or sessions in the chat interface. This enables proper UI state management when switching between views.

src/renderer/src/store/runtime.ts

@@ -13,6 +13,7 @@ export interface ChatState {
   /** UI state. Map agent id to active session id.
    *  null represents no active session  */
   activeSessionId: Record<string, string | null>
+  activeTopicOrSession: 'topic' | 'session'
   activeTabId: Tab
   /** topic ids that are currently being renamed */
   renamingTopics: string[]
@@ -87,6 +88,7 @@ const initialState: RuntimeState = {
     activeTabId: 'assistants',
     activeTopic: null,
     activeAgentId: null,
+    activeTopicOrSession: 'topic',
     activeSessionId: {},
     renamingTopics: [],
     newlyRenamedTopics: []
@@ -162,6 +164,9 @@ const runtimeSlice = createSlice({
     setActiveTabIdAction: (state, action: PayloadAction<Tab>) => {
       state.chat.activeTabId = action.payload
     },
+    setActiveTopicOrSessionAction: (state, action: PayloadAction<'topic' | 'session'>) => {
+      state.chat.activeTopicOrSession = action.payload
+    },
     setRenamingTopics: (state, action: PayloadAction<string[]>) => {
       state.chat.renamingTopics = action.payload
     },
@@ -203,6 +208,7 @@ export const {
   setActiveAgentId,
   setActiveSessionIdAction,
   setActiveTabIdAction,
+  setActiveTopicOrSessionAction,
   setRenamingTopics,
   setNewlyRenamedTopics,
   // WebSearch related actions