fix(docs): remove unused preview block export

Author: waleedlatif1

apps/docs/components/workflow-preview/index.ts

@@ -39,7 +39,6 @@ export {
   WORKFLOW_CALL_WORKFLOW,
 } from '@/components/workflow-preview/examples'
 export type {
-  PreviewBlock,
   PreviewTool,
   PreviewWorkflow,
 } from '@/components/workflow-preview/workflow-data'

apps/docs/components/workflow-preview/workflow-data.ts

@@ -28,7 +28,7 @@ export interface PreviewTool {
  * A single block in a preview workflow. Presentational shape — authored by hand
  * for docs diagrams, not the app's full serialized block state.
  */
-export interface PreviewBlock {
+interface PreviewBlock {
   id: string
   name: string
   type: string