refactor(chat): drop branch groups state

src/routes/chat.ts

@@ -71,7 +71,6 @@ const sessionStateSchema = z.object({
   title: z.string().max(120).optional(),
   is_title_manually_edited: z.boolean().optional(),
   messages: z.array(z.unknown()).default([]),
-  branch_groups: z.array(z.unknown()).default([]),
 });
 
 const activeRuns = new Map<string, ActiveRun>();
@@ -205,7 +204,6 @@ export const buildChatRouter = (
       status: sessionRecord.status,
       session_id: sessionRecord.sessionId,
       messages: state?.messages ?? [],
-      branch_groups: state?.branchGroups ?? [],
       parent_session_id: sessionRecord.parentSessionId,
       is_streaming: activeRuns.get(sessionRecord.sessionId)?.status === "running",
       run_status: getSessionRunStatus(sessionRecord.sessionId),
@@ -310,7 +308,6 @@ export const buildChatRouter = (
       sessionId: nextRecord.sessionId,
       isTitleManuallyEdited: parsed.data.is_title_manually_edited,
       messages: parsed.data.messages,
-      branchGroups: parsed.data.branch_groups,
     });
     const latestTurn = extractLatestFrontendTurn(parsed.data.messages);
     if (latestTurn) {
@@ -619,7 +616,6 @@ export const buildChatRouter = (
         baseMessages,
         parsed.data.message,
       );
-      const branchGroups = initialSessionState?.branchGroups ?? [];
       const activeRun: ActiveRun = {
         clientSessionId,
         controller: abortController,
@@ -636,14 +632,12 @@ export const buildChatRouter = (
         sessionId: activeSessionRecord.sessionId,
         isTitleManuallyEdited: initialSessionState?.isTitleManuallyEdited ?? false,
         messages: initialMessages,
-        branchGroups,
       });
       const queueSessionUiStatePersist = () => {
         const snapshot = {
           sessionId: activeSessionRecord.sessionId,
           isTitleManuallyEdited: initialSessionState?.isTitleManuallyEdited ?? false,
           messages: activeRun.messages,
-          branchGroups,
         };
         persistQueue = persistQueue
           .catch((error) => {

src/routes/chatAuxiliaryRoutes.ts

@@ -135,7 +135,6 @@ export const registerChatAuxiliaryRoutes = (
             sessionId: sessionRecord.sessionId,
             isTitleManuallyEdited: currentState?.isTitleManuallyEdited ?? false,
             messages: run.messages,
-            branchGroups: currentState?.branchGroups ?? [],
           });
         }
         for (const subscriber of run.subscribers) {

src/routes/chatInteractionRoutes.ts

@@ -96,7 +96,6 @@ export const registerChatInteractionRoutes = (
           sessionId: sessionRecord.sessionId,
           isTitleManuallyEdited: currentState?.isTitleManuallyEdited ?? false,
           messages: run.messages,
-          branchGroups: currentState?.branchGroups ?? [],
         });
       };
 
@@ -221,7 +220,6 @@ export const registerChatInteractionRoutes = (
           sessionId: sessionRecord.sessionId,
           isTitleManuallyEdited: currentState?.isTitleManuallyEdited ?? false,
           messages: run.messages,
-          branchGroups: currentState?.branchGroups ?? [],
         });
       };
 
@@ -353,7 +351,6 @@ export const registerChatInteractionRoutes = (
           sessionId: sessionRecord.sessionId,
           isTitleManuallyEdited: currentState?.isTitleManuallyEdited ?? false,
           messages: run.messages,
-          branchGroups: currentState?.branchGroups ?? [],
         });
       };
 

src/sessions/uiStateStore.ts

@@ -13,7 +13,6 @@ export type SessionUiStateRecord = {
   sessionId: string;
   isTitleManuallyEdited?: boolean;
   messages: unknown[];
-  branchGroups: unknown[];
 };
 
 type SessionUiStateContext = {