fix: file preview URLs and milestone web link saving

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/detail/ExcelPreview.tsx

@@ -1,5 +1,6 @@
 import { useEffect, useState } from 'react';
 import * as XLSX from 'xlsx';
+import { fileDownloadUrl, fileViewUrl } from '../../lib/apiClient';
 
 interface ExcelPreviewProps {
   fileId: string;
@@ -21,7 +22,7 @@ export function ExcelPreview({ fileId, fileName }: ExcelPreviewProps) {
 
     (async () => {
       try {
-        const res = await fetch(`/api/files/${fileId}/view`);
+        const res = await fetch(fileViewUrl(fileId));
         if (!res.ok) throw new Error('파일을 불러올 수 없습니다.');
         const buffer = await res.arrayBuffer();
         const wb = XLSX.read(buffer, { type: 'array' });
@@ -48,7 +49,7 @@ export function ExcelPreview({ fileId, fileName }: ExcelPreviewProps) {
       <div className="flex h-full w-full flex-col items-center justify-center gap-3 p-6 text-center">
         <p className="text-lg text-white/60">{error}</p>
         <a
-          href={`/api/files/${fileId}/download`}
+          href={fileDownloadUrl(fileId)}
           className="rounded bg-white/10 px-4 py-2 text-sm font-bold text-white hover:bg-white/20"
         >
           {fileName} 다운로드

frontend/src/components/detail/ResultPreview.tsx

@@ -1,6 +1,7 @@
 import { useState, useEffect, useCallback } from 'react';
 import { createPortal } from 'react-dom';
 import { ExcelPreview } from './ExcelPreview';
+import { fileViewUrl } from '../../lib/apiClient';
 import { openLinkOnRightMonitor } from '../../lib/dualMonitor';
 import { fileDisplayName, isExcelFile, isVideoFile } from '../../lib/fileDisplay';
 import type { FileRecord, MilestoneLink } from '../../types';
@@ -53,7 +54,7 @@ export function ResultPreview({ files, links, hasSelectedStage }: ResultPreviewP
       if (isExcel) {
         return <ExcelPreview fileId={activeFile.id} fileName={label} />;
       }
-      const src = `/api/files/${activeFile.id}/view`;
+      const src = fileViewUrl(activeFile.id);
       if (isImage) {
         return (
           <img

frontend/src/components/detail/StageModal.tsx

@@ -291,6 +291,15 @@ export function StageModal({
     if (editTarget?.type === 'file') applyFileEdit();
     if (editTarget?.type === 'link') applyLinkEdit();
 
+    let saveForm = form;
+    const pendingUrl = linkUrl.trim();
+    if (editTarget?.type !== 'link' && pendingUrl) {
+      saveForm = {
+        ...form,
+        links: [...form.links, { label: linkLabel.trim() || pendingUrl, url: pendingUrl }],
+      };
+    }
+
     const sorted = [...fileRows].sort((a, b) => a.sortOrder - b.sortOrder);
     const uploads: PendingFileUpload[] = [];
     const existingEdits: ExistingFileEdit[] = [];
@@ -312,7 +321,7 @@ export function StageModal({
       }
     });
 
-    await onSave(form, {
+    await onSave(saveForm, {
       uploads,
       existingEdits,
       deletedFileIds,

frontend/src/lib/apiClient.ts

@@ -16,6 +16,14 @@ export const apiClient = axios.create({
   },
 });
 
+export function fileViewUrl(fileId: string): string {
+  return `${baseURL}/files/${fileId}/view`;
+}
+
+export function fileDownloadUrl(fileId: string): string {
+  return `${baseURL}/files/${fileId}/download`;
+}
+
 apiClient.interceptors.request.use((config) => {
   if (config.data instanceof FormData) {
     delete config.headers['Content-Type'];

frontend/src/pages/DetailPage.tsx

@@ -286,7 +286,7 @@ function DetailView({ task }: { task: TaskWithRelations }) {
         startDate: data.startDate || undefined,
         dueDate: data.dueDate || undefined,
         progress: data.progress,
-        links: data.links.length > 0 ? JSON.stringify(data.links) : undefined,
+        links: data.links,
       };
 
       let milestoneId: string;