feat(skill): add oRPC contract and hook for file download URL

Add frontend oRPC integration for the existing backend download URL
endpoint to enable file downloads from the asset tree.

web/contract/console/app-asset.ts

@@ -1,6 +1,7 @@
 import type {
   AppAssetDeleteResponse,
   AppAssetFileContentResponse,
+  AppAssetFileDownloadUrlResponse,
   AppAssetNode,
   AppAssetPublishResponse,
   AppAssetTreeResponse,
@@ -54,6 +55,16 @@ export const getFileContentContract = base
   }>())
   .output(type<AppAssetFileContentResponse>())
 
+export const getFileDownloadUrlContract = base
+  .route({
+    path: '/apps/{appId}/assets/files/{nodeId}/download-url',
+    method: 'GET',
+  })
+  .input(type<{
+    params: { appId: string, nodeId: string }
+  }>())
+  .output(type<AppAssetFileDownloadUrlResponse>())
+
 export const updateFileContentContract = base
   .route({
     path: '/apps/{appId}/assets/files/{nodeId}',

web/contract/router.ts

@@ -4,6 +4,7 @@ import {
   createFolderContract,
   deleteNodeContract,
   getFileContentContract,
+  getFileDownloadUrlContract,
   moveNodeContract,
   publishContract,
   renameNodeContract,
@@ -50,6 +51,7 @@ export const consoleRouterContract = {
     createFolder: createFolderContract,
     createFile: createFileContract,
     getFileContent: getFileContentContract,
+    getFileDownloadUrl: getFileDownloadUrlContract,
     updateFileContent: updateFileContentContract,
     deleteNode: deleteNodeContract,
     renameNode: renameNodeContract,

web/service/use-app-asset.ts

@@ -104,6 +104,14 @@ export const useGetAppAssetFileContent = (appId: string, nodeId: string) => {
   })
 }
 
+export const useGetAppAssetFileDownloadUrl = (appId: string, nodeId: string, options?: { enabled?: boolean }) => {
+  return useQuery({
+    queryKey: consoleQuery.appAsset.getFileDownloadUrl.queryKey({ input: { params: { appId, nodeId } } }),
+    queryFn: () => consoleClient.appAsset.getFileDownloadUrl({ params: { appId, nodeId } }),
+    enabled: (options?.enabled ?? true) && !!appId && !!nodeId,
+  })
+}
+
 export const useUpdateAppAssetFileContent = () => {
   const queryClient = useQueryClient()
   return useMutation({

web/types/app-asset.ts

@@ -70,6 +70,14 @@ export type AppAssetFileContentResponse = {
   content: string
 }
 
+/**
+ * File download URL response (GET /apps/{app_id}/assets/files/{node_id}/download-url)
+ */
+export type AppAssetFileDownloadUrlResponse = {
+  /** Presigned download URL */
+  download_url: string
+}
+
 /**
  * Delete node response (DELETE /apps/{app_id}/assets/nodes/{node_id})
  */