fix(web-ui): stabilize flow chat session activation

src/web-ui/src/app/components/NavPanel/NavSearchDialog.tsx

@@ -10,7 +10,7 @@ import { useMyAgentStore } from '@/app/scenes/my-agent/myAgentStore';
 import { useNurseryStore } from '@/app/scenes/profile/nurseryStore';
 import { flowChatStore } from '@/flow_chat/store/FlowChatStore';
 import { findWorkspaceForSession } from '@/flow_chat/utils/workspaceScope';
-import { openMainSession } from '@/flow_chat/services/openBtwSession';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import type { FlowChatState, Session } from '@/flow_chat/types/flow-chat';
 import type { SessionMetadata } from '@/shared/types/session-history';
 import type { WorkspaceInfo } from '@/shared/types';

src/web-ui/src/app/components/NavPanel/sections/sessions/SessionsSection.tsx

@@ -19,9 +19,9 @@ import { createLogger } from '@/shared/utils/logger';
 import { useAgentCanvasStore } from '@/app/components/panels/content-canvas/stores';
 import {
   openBtwSessionInAuxPane,
-  openMainSession,
   selectActiveBtwSessionTab,
-} from '@/flow_chat/services/openBtwSession';
+} from '@/flow_chat/services/btwSessionPane';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import {
   dispatchHistorySessionOpenIntent,
   shouldShowHistorySessionOpenIntent,
@@ -47,7 +47,6 @@ import type {
   BackgroundSubagentActivityItem,
 } from '@/flow_chat/utils/backgroundSubagentActivity';
 import { computeFixedPopoverPosition } from '@/shared/utils/fixedPopoverViewport';
-import { sessionAPI } from '@/infrastructure/api/service-api/SessionAPI';
 import { confirmWarning } from '@/component-library/components/ConfirmDialog/confirmService';
 import { scheduleAfterStartupPaint, scheduleAfterStartupSignal } from '@/shared/utils/startupTaskScheduling';
 import {
@@ -803,15 +802,13 @@ const SessionsSection: React.FC<SessionsSectionProps> = ({
       );
       if (!confirmed) return;
       try {
-        await sessionAPI.archiveSession(sessionId, workspacePath || '', remoteConnectionId || undefined, remoteSshHost || undefined);
-        // Remove from in-memory state only — do NOT delete from disk
-        flowChatManager.discardLocalSession(sessionId);
+        await flowChatManager.archiveChatSession(sessionId);
         window.dispatchEvent(new CustomEvent('bitfun:session-archived'));
       } catch (err) {
         log.error('Failed to archive session', err);
       }
     },
-    [workspacePath, remoteConnectionId, remoteSshHost, t]
+    [t]
   );
 
   const handleStartEdit = useCallback(

src/web-ui/src/app/components/NavPanel/sections/workspaces/WorkspaceItem.tsx

@@ -19,7 +19,7 @@ import { workspaceAPI } from '@/infrastructure/api';
 import { agentAPI } from '@/infrastructure/api/service-api/AgentAPI';
 import { notificationService } from '@/shared/notification-system';
 import { flowChatManager } from '@/flow_chat/services/FlowChatManager';
-import { openMainSession } from '@/flow_chat/services/openBtwSession';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import {
   getHistorySessionOpenTransitionSnapshot,
   subscribeHistorySessionOpenTransition,

src/web-ui/src/app/components/NavPanel/sections/workspaces/WorkspaceSessionBatchModal.tsx

@@ -220,20 +220,10 @@ const WorkspaceSessionBatchModal: React.FC<WorkspaceSessionBatchModalProps> = ({
     setActionKind('archive');
     try {
       const results = await Promise.allSettled(
-        selectedIds.map(sessionId =>
-          sessionAPI.archiveSession(
-            sessionId,
-            workspacePath,
-            remoteConnectionId || undefined,
-            remoteSshHost || undefined
-          )
-        )
+        selectedIds.map(sessionId => flowChatManager.archiveChatSession(sessionId))
       );
       const successCount = results.filter(result => result.status === 'fulfilled').length;
       if (successCount > 0) {
-        selectedIds.forEach(sessionId => {
-          flowChatManager.discardLocalSession(sessionId);
-        });
         await refreshWorkspaceSessions();
         window.dispatchEvent(new CustomEvent('bitfun:session-archived'));
         notificationService.success(t('nav.sessions.archivedAll', { count: successCount }), { duration: 3000 });
@@ -251,8 +241,6 @@ const WorkspaceSessionBatchModal: React.FC<WorkspaceSessionBatchModalProps> = ({
   }, [
     loadSessions,
     refreshWorkspaceSessions,
-    remoteConnectionId,
-    remoteSshHost,
     selectedCount,
     selectedSessionIds,
     t,
@@ -274,32 +262,23 @@ const WorkspaceSessionBatchModal: React.FC<WorkspaceSessionBatchModalProps> = ({
     const deletionPlan = getDeletionPlan(selectedSessionIds, sessions);
     setActionKind('delete');
     try {
-      const results = await Promise.allSettled(
-        deletionPlan.allIds.map(sessionId =>
-          sessionAPI.deleteSession(
-            sessionId,
-            workspacePath,
-            remoteConnectionId || undefined,
-            remoteSshHost || undefined
-          )
-        )
-      );
       const successIds = new Set<string>();
-      results.forEach((result, index) => {
-        if (result.status === 'fulfilled') {
-          successIds.add(deletionPlan.allIds[index]);
-        }
-      });
 
-      const removableRootIds = deletionPlan.rootIds.filter(rootId => {
+      for (const rootId of deletionPlan.rootIds) {
         const cascadeIds = getDeletionPlan(new Set([rootId]), sessions).allIds;
-        return cascadeIds.every(id => successIds.has(id));
-      });
+        try {
+          await flowChatManager.deleteChatSession(rootId);
+          cascadeIds.forEach(id => successIds.add(id));
+        } catch (error) {
+          log.error('Failed to delete selected root session', {
+            error,
+            rootSessionId: rootId,
+            workspacePath,
+          });
+        }
+      }
 
-      if (removableRootIds.length > 0) {
-        removableRootIds.forEach(sessionId => {
-          flowChatManager.discardLocalSession(sessionId);
-        });
+      if (successIds.size > 0) {
         await refreshWorkspaceSessions();
         notificationService.success(t('nav.sessions.deletedSelected', { count: successIds.size }), { duration: 3000 });
       }
@@ -316,8 +295,6 @@ const WorkspaceSessionBatchModal: React.FC<WorkspaceSessionBatchModalProps> = ({
   }, [
     loadSessions,
     refreshWorkspaceSessions,
-    remoteConnectionId,
-    remoteSshHost,
     selectedCount,
     selectedSessionIds,
     sessions,

src/web-ui/src/app/components/panels/content-canvas/ContentCanvas.tsx

@@ -12,7 +12,8 @@ import { useCanvasStore } from './stores';
 import { useTabLifecycle, useKeyboardShortcuts, usePanelTabCoordinator } from './hooks';
 import type { AnchorPosition } from './types';
 import { TAB_EVENTS } from './types';
-import { openMainSession, selectActiveBtwSessionTab } from '@/flow_chat/services/openBtwSession';
+import { selectActiveBtwSessionTab } from '@/flow_chat/services/btwSessionPane';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import { isSamePath } from '@/shared/utils/pathUtils';
 import './ContentCanvas.scss';
 export interface ContentCanvasProps {

src/web-ui/src/app/components/panels/review-platform/ReviewPlatformPanel.tsx

@@ -27,7 +27,7 @@ import { reviewPlatformAPI, systemAPI, type ReviewPlatformAccount, type ReviewPl
 import { createLogger } from '@/shared/utils/logger';
 import { notificationService } from '@/shared/notification-system';
 import { i18nService } from '@/infrastructure/i18n';
-import { openMainSession } from '@/flow_chat/services/openBtwSession';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import { flowChatStore } from '@/flow_chat/store/FlowChatStore';
 import type { FlowToolItem, Session } from '@/flow_chat/types/flow-chat';
 import { findLatestCodeReviewResult, summarizeCodeReviewResult } from '@/flow_chat/utils/reviewSessionSummary';

src/web-ui/src/app/layout/FloatingMiniChat.tsx

@@ -20,6 +20,7 @@ import {
 } from 'lucide-react';
 import { flowChatStore } from '../../flow_chat/store/FlowChatStore';
 import { syncSessionToModernStore } from '../../flow_chat/services/storeSync';
+import { activateMainSession } from '../../flow_chat/services/sessionActivation';
 import { useToolbarModeContext } from '../../flow_chat/components/toolbar-mode/ToolbarModeContext';
 import type { FlowChatState } from '../../flow_chat/types/flow-chat';
 import { compareSessionsForDisplay } from '../../flow_chat/utils/sessionOrdering';
@@ -113,9 +114,11 @@ export const FloatingMiniChat: React.FC = () => {
   const handleSwitchSession = useCallback((e: React.MouseEvent, sessionId: string) => {
     e.stopPropagation();
     e.preventDefault();
-    flowChatStore.switchSession(sessionId);
-    syncSessionToModernStore(sessionId);
-    setShowSessionPicker(false);
+    void activateMainSession(sessionId).then((activated) => {
+      if (activated) {
+        setShowSessionPicker(false);
+      }
+    });
   }, []);
 
   const handleCancel = useCallback(() => {

src/web-ui/src/app/scenes/profile/views/AssistantQuickInput.tsx

@@ -15,7 +15,7 @@ import { useTranslation } from 'react-i18next';
 import { IconButton, Textarea } from '@/component-library';
 import { ModelSelector } from '@/flow_chat/components/ModelSelector';
 import { flowChatManager } from '@/flow_chat/services/FlowChatManager';
-import { openMainSession } from '@/flow_chat/services/openBtwSession';
+import { openMainSession } from '@/flow_chat/services/sessionActivation';
 import { useImeEnterGuard } from '@/flow_chat/hooks/useImeEnterGuard';
 import { useWorkspaceContext } from '@/infrastructure/contexts/WorkspaceContext';
 import { notificationService } from '@/shared/notification-system';

src/web-ui/src/app/services/openAgentCompanionSession.test.ts

@@ -5,13 +5,17 @@ import type { Session } from '@/flow_chat/types/flow-chat';
 const mocks = vi.hoisted(() => ({
   openBtwSessionInAuxPane: vi.fn(),
   openMainSession: vi.fn(() => Promise.resolve()),
-  switchSession: vi.fn(),
+  activateMainSession: vi.fn(() => Promise.resolve(true)),
   sessions: new Map<string, Session>(),
 }));
 
-vi.mock('@/flow_chat/services/openBtwSession', () => ({
+vi.mock('@/flow_chat/services/btwSessionPane', () => ({
   openBtwSessionInAuxPane: (...args: unknown[]) => mocks.openBtwSessionInAuxPane(...args),
+}));
+
+vi.mock('@/flow_chat/services/sessionActivation', () => ({
   openMainSession: (...args: unknown[]) => mocks.openMainSession(...args),
+  activateMainSession: (...args: unknown[]) => mocks.activateMainSession(...args),
 }));
 
 vi.mock('@/flow_chat/store/FlowChatStore', () => ({
@@ -20,7 +24,6 @@ vi.mock('@/flow_chat/store/FlowChatStore', () => ({
       getState: () => ({
         sessions: mocks.sessions,
       }),
-      switchSession: (...args: unknown[]) => mocks.switchSession(...args),
     }),
   },
 }));
@@ -43,7 +46,7 @@ describe('openAgentCompanionSession', () => {
   beforeEach(() => {
     mocks.openBtwSessionInAuxPane.mockClear();
     mocks.openMainSession.mockClear();
-    mocks.switchSession.mockClear();
+    mocks.activateMainSession.mockClear();
     mocks.sessions.clear();
   });
 
@@ -64,7 +67,7 @@ describe('openAgentCompanionSession', () => {
       parentSessionId: 'parent-session',
       workspacePath: 'D:/workspace/project',
     });
-    expect(mocks.switchSession).not.toHaveBeenCalled();
+    expect(mocks.activateMainSession).not.toHaveBeenCalled();
   });
 
   it('keeps regular sessions on the main chat route', async () => {
@@ -73,7 +76,7 @@ describe('openAgentCompanionSession', () => {
     const opened = await openAgentCompanionSession('session-1');
 
     expect(opened).toBe(true);
-    expect(mocks.switchSession).toHaveBeenCalledWith('session-1');
+    expect(mocks.activateMainSession).toHaveBeenCalledWith('session-1');
     expect(mocks.openMainSession).not.toHaveBeenCalled();
     expect(mocks.openBtwSessionInAuxPane).not.toHaveBeenCalled();
   });

src/web-ui/src/app/services/openAgentCompanionSession.ts

@@ -1,5 +1,6 @@
 import { FlowChatStore } from '@/flow_chat/store/FlowChatStore';
-import { openBtwSessionInAuxPane, openMainSession } from '@/flow_chat/services/openBtwSession';
+import { openBtwSessionInAuxPane } from '@/flow_chat/services/btwSessionPane';
+import { activateMainSession, openMainSession } from '@/flow_chat/services/sessionActivation';
 import { resolveSessionRelationship } from '@/flow_chat/utils/sessionMetadata';
 
 export async function openAgentCompanionSession(sessionId: string): Promise<boolean> {
@@ -22,6 +23,5 @@ export async function openAgentCompanionSession(sessionId: string): Promise<bool
     return true;
   }
 
-  flowChatStore.switchSession(sessionId);
-  return true;
+  return activateMainSession(sessionId);
 }

src/web-ui/src/flow_chat/components/ChatInput.tsx

@@ -60,7 +60,7 @@ import { createLogger } from '@/shared/utils/logger';
 import { Tooltip, IconButton, confirmWarning } from '@/component-library';
 import { PendingQueuePanel } from './PendingQueuePanel';
 import { useAgentCanvasStore } from '@/app/components/panels/content-canvas/stores';
-import { openBtwSessionInAuxPane, selectActiveBtwSessionTab } from '../services/openBtwSession';
+import { openBtwSessionInAuxPane, selectActiveBtwSessionTab } from '../services/btwSessionPane';
 import { resolveSessionRelationship } from '../utils/sessionMetadata';
 import {
   DEFAULT_CHAT_INPUT_MODE_CONFIG_PATH,

src/web-ui/src/flow_chat/components/modern/ModernFlowChatContainer.tsx

@@ -44,7 +44,7 @@ import { parsePullRequestUrl } from '@/shared/utils/pullRequestLinks';
 import { createBackgroundCommandOutputTab, createReviewPlatformPullRequestDetailTab } from '@/shared/utils/tabUtils';
 import { isAcpFlowSession } from '../../utils/acpSession';
 import { flowChatStore } from '../../store/FlowChatStore';
-import { openBtwSessionInAuxPane } from '../../services/openBtwSession';
+import { openBtwSessionInAuxPane } from '../../services/btwSessionPane';
 import { resolveThreadGoalHeaderTitle } from '../../utils/threadGoalDisplay';
 import {
   findDialogTurn,

src/web-ui/src/flow_chat/components/modern/SessionFilesBadge.test.tsx

@@ -76,7 +76,7 @@ vi.mock('../../services/BtwThreadService', () => ({
   createBtwChildSession: vi.fn(),
 }));
 
-vi.mock('../../services/openBtwSession', () => ({
+vi.mock('../../services/btwSessionPane', () => ({
   openBtwSessionInAuxPane: vi.fn(),
 }));
 

src/web-ui/src/flow_chat/components/modern/SessionFilesBadge.tsx

@@ -25,7 +25,7 @@ import { notificationService } from '../../../shared/notification-system';
 import { createLogger } from '@/shared/utils/logger';
 import { runWithConcurrencyLimit } from '@/shared/utils/runWithConcurrencyLimit';
 import { createBtwChildSession } from '../../services/BtwThreadService';
-import { openBtwSessionInAuxPane } from '../../services/openBtwSession';
+import { openBtwSessionInAuxPane } from '../../services/btwSessionPane';
 import {
   buildDeepReviewLaunchFromSessionFiles,
   buildDeepReviewPreviewFromSessionFiles,

src/web-ui/src/flow_chat/components/subagent/SubagentProjectionView.test.tsx

@@ -52,7 +52,7 @@ vi.mock('../../store/FlowChatStore', () => ({
   },
 }));
 
-vi.mock('../../services/openBtwSession', () => ({
+vi.mock('../../services/btwSessionPane', () => ({
   ensureBtwSessionAvailable: (...args: unknown[]) => ensureBtwSessionAvailableMock(...args),
 }));
 

src/web-ui/src/flow_chat/components/subagent/SubagentProjectionView.tsx

@@ -8,7 +8,7 @@ import { taskCollapseStateManager } from '../../store/TaskCollapseStateManager';
 import { SmoothHeightCollapse } from '../modern/SmoothHeightCollapse';
 import { FlowChatStore } from '../../store/FlowChatStore';
 import { getSubagentProjectionState } from '../../utils/subagentProjection';
-import { ensureBtwSessionAvailable } from '../../services/openBtwSession';
+import { ensureBtwSessionAvailable } from '../../services/btwSessionPane';
 import './SubagentProjectionView.scss';
 
 interface SubagentProjectionViewProps {

src/web-ui/src/flow_chat/components/toolbar-mode/ToolbarMode.tsx

@@ -24,7 +24,7 @@ import {
 } from 'lucide-react';
 import { useToolbarModeContext } from './ToolbarModeContext';
 import { flowChatStore } from '../../store/FlowChatStore';
-import { syncSessionToModernStore } from '../../services/storeSync';
+import { activateMainSession } from '../../services/sessionActivation';
 import { FlowChatState } from '../../types/flow-chat';
 import { compareSessionsForDisplay } from '../../utils/sessionOrdering';
 import { createLogger } from '@/shared/utils/logger';
@@ -235,9 +235,11 @@ export const ToolbarMode: React.FC = () => {
   const handleSwitchSession = useCallback((e: React.MouseEvent, sessionId: string) => {
     e.stopPropagation();
     e.preventDefault();
-    flowChatStore.switchSession(sessionId);
-    syncSessionToModernStore(sessionId);
-    setShowSessionPicker(false);
+    void activateMainSession(sessionId).then((activated) => {
+      if (activated) {
+        setShowSessionPicker(false);
+      }
+    });
   }, []);
 
   const handleCancel = useCallback(() => {

src/web-ui/src/flow_chat/deep-review/launch/DeepReviewService.ts

@@ -1,7 +1,7 @@
 import { agentAPI } from '@/infrastructure/api';
 import { createLogger } from '@/shared/utils/logger';
 import { createBtwChildSession } from '../../services/BtwThreadService';
-import { closeBtwSessionInAuxPane, openBtwSessionInAuxPane } from '../../services/openBtwSession';
+import { closeBtwSessionInAuxPane, openBtwSessionInAuxPane } from '../../services/btwSessionPane';
 import { FlowChatManager } from '../../services/FlowChatManager';
 import { flowChatStore } from '../../store/FlowChatStore';
 import { insertReviewSessionSummaryMarker } from '../../services/ReviewSessionMarkerService';

src/web-ui/src/flow_chat/services/DeepReviewService.test.ts

@@ -41,7 +41,7 @@ vi.mock('./BtwThreadService', () => ({
   createBtwChildSession: (...args: any[]) => mockCreateBtwChildSession(...args),
 }));
 
-vi.mock('./openBtwSession', () => ({
+vi.mock('./btwSessionPane', () => ({
   closeBtwSessionInAuxPane: (...args: any[]) => mockCloseBtwSessionInAuxPane(...args),
   openBtwSessionInAuxPane: (...args: any[]) => mockOpenBtwSessionInAuxPane(...args),
 }));