Revert "fix: remove redudant export for client plugin"

This reverts commit 48b259100b9cfe2e372eb9fe0924a783988f5a8e.

packages/client/ui-sidebar/src/client/index.ts

@@ -3,10 +3,6 @@
  * sidebar slot; tree derivation materialized in a plugin-owned snapshot
  * store (pure consumer — no ctx service). Contract: api-contracts v3
  * section 6; props composition in contract/slots.ts.
- *
- * Export discipline: the public surface is the plugin body (apply/inject)
- * plus the contract types. Implementation components and derivation live in
- * their modules; tests reach them via src paths.
  */
 import type { RootBinding } from '@deepseek-ai/dsh-client-ui-slots'
 import type { ClientContext, SessionId } from '@deepseek-ai/dsh-client-runtime/client'
@@ -14,6 +10,17 @@ import type { SidebarRootInjected } from './contract/slots.ts'
 import { createSidebarTreeStore } from './store.ts'
 import { SidebarRoot } from './SidebarRoot.tsx'
 
+export {
+  deriveRows, formatRelativeTime, projectLabel,
+  UNGROUPED_KEY, UNGROUPED_LABEL,
+  type ProjectRow, type SessionRow, type SidebarRow, type TreeView,
+} from './tree.ts'
+export {
+  createSidebarTreeStore,
+  type GroupBy, type SidebarTreeState, type SidebarTreeStore,
+} from './store.ts'
+export { ProjectRowItem, SessionRowItem } from './Rows.tsx'
+export { SidebarRoot } from './SidebarRoot.tsx'
 export type {
   SidebarActions, SidebarRootComponentProps, SidebarRootInjected, SidebarTreeActions,
 } from './contract/slots.ts'