feat(ui): redirect tenant switch away from tenant-scoped routes

Switching the active tenant triggers window.location.reload() to
re-key every cached store / open SSE stream / in-flight request.
The catch: when the user is currently sitting on a route whose URL
embeds a tenant-scoped resource id, the new tenant lands on a
404/403 and the user sees a blank screen.

Three risky route shapes today:

  /platform/knowledge-bases/:kbId
  /platform/knowledge-bases/:kbId/creatChat
  /platform/chat/:chatid

Add a tiny tenantSwitch utility (navigateAfterTenantSwitch) that
matches the current path against this list and redirects to
/platform/knowledge-bases — the platform default landing, always
renderable regardless of role. Anything else (settings, agent
list, KB list, etc.) continues to reload its current path because
those views handle empty/forbidden data gracefully.

Both tenant-switch call sites (TenantSelector and UserMenu) use
the helper so the matrix lives in one place; future tenant-scoped
routes only need to add a regex to the list.

frontend/src/components/TenantSelector.vue

@@ -82,6 +82,7 @@ import { useAuthStore } from '@/stores/auth'
 import { searchTenants, type TenantInfo } from '@/api/tenant'
 import { useI18n } from 'vue-i18n'
 import { MessagePlugin } from 'tdesign-vue-next'
+import { navigateAfterTenantSwitch } from '@/utils/tenantSwitch'
 
 const { t } = useI18n()
 const authStore = useAuthStore()
@@ -161,7 +162,7 @@ const clearSearch = () => {
 const selectTenant = (tenantId: number) => {
   // 找到选中的租户信息
   const selectedTenant = tenants.value.find(t => t.id === tenantId)
-  
+
   if (tenantId === defaultTenantId.value) {
     authStore.setSelectedTenant(null, null)
   } else {
@@ -169,8 +170,9 @@ const selectTenant = (tenantId: number) => {
   }
   closeDropdown()
   MessagePlugin.success(t('tenant.switchSuccess'))
+  // 切换租户后跳转到新租户下安全的入口（详见 tenantSwitch.ts 注释）。
   setTimeout(() => {
-    window.location.reload()
+    navigateAfterTenantSwitch()
   }, 500)
 }
 

frontend/src/components/UserMenu.vue

@@ -214,6 +214,7 @@ import { getCurrentUser, logout as logoutApi } from '@/api/auth'
 import { useI18n } from 'vue-i18n'
 import IMChannelsOverviewPanel from '@/components/IMChannelsOverviewPanel.vue'
 import { listAllIMChannels, type IMChannelOverview } from '@/api/agent'
+import { navigateAfterTenantSwitch } from '@/utils/tenantSwitch'
 
 const { t } = useI18n()
 
@@ -372,10 +373,12 @@ const switchToTenant = (m: Membership) => {
   closeAll()
   MessagePlugin.success(t('tenant.switchSuccess'))
   // Hard reload so every cached store / open SSE stream / in-flight
-  // request gets re-keyed under the new tenant. Same approach as
-  // TenantSelector.vue.
+  // request gets re-keyed under the new tenant. If the current path
+  // embeds a tenant-scoped resource id, reload would white-screen the
+  // user; navigateAfterTenantSwitch redirects to the platform home in
+  // that case. Same helper as TenantSelector.vue.
   setTimeout(() => {
-    window.location.reload()
+    navigateAfterTenantSwitch()
   }, 400)
 }
 

frontend/src/utils/tenantSwitch.ts

@@ -0,0 +1,44 @@
+// Tenant-switch navigation helper.
+//
+// Switching the active tenant triggers a full page reload so every cached
+// store / open SSE stream / in-flight request gets re-keyed under the new
+// tenant. The catch: if the user is currently sitting on a route whose URL
+// embeds a tenant-scoped resource id (KB id, session id), reloading lands
+// them on a 403/empty page in the new tenant — visible to the user as a
+// blank screen. For those routes we redirect to the platform default
+// landing page instead, which is always safe regardless of role.
+//
+// Anything not on this list keeps its current path on reload (settings,
+// agent list, KB list, etc. — they re-fetch under the new tenant
+// naturally).
+
+const TENANT_SCOPED_ROUTE_PATTERNS: RegExp[] = [
+  /^\/platform\/knowledge-bases\/[^/]+$/,             // /platform/knowledge-bases/:kbId
+  /^\/platform\/knowledge-bases\/[^/]+\/creatChat$/,  // /platform/knowledge-bases/:kbId/creatChat
+  /^\/platform\/chat\/[^/]+$/,                        // /platform/chat/:chatid
+]
+
+const SAFE_FALLBACK_PATH = '/platform/knowledge-bases'
+
+/**
+ * Return the URL to navigate to after a tenant switch. If the current path
+ * embeds a tenant-scoped id, returns the safe fallback; otherwise returns
+ * null to signal "reload current path".
+ */
+export function tenantSwitchTargetPath(currentPath: string): string | null {
+  const isScoped = TENANT_SCOPED_ROUTE_PATTERNS.some(re => re.test(currentPath))
+  return isScoped ? SAFE_FALLBACK_PATH : null
+}
+
+/**
+ * Perform the post-switch navigation. Either redirect to the safe fallback
+ * (if the current page is tenant-scoped) or hard-reload the current page.
+ */
+export function navigateAfterTenantSwitch(): void {
+  const target = tenantSwitchTargetPath(window.location.pathname)
+  if (target !== null) {
+    window.location.href = target
+  } else {
+    window.location.reload()
+  }
+}