feat: implement video site per README spec

- Express + EJS + express-session stack (auth/navbar ported from minecraft_launcher)
- Public: main folder list, folder video grid, internal popup player (/player/:videoId)
- Admin (/op): login, folder CRUD with right-click context menu + add-folder modal
- Admin folder: video grid with right-click edit/rename/delete, "영상 추가" -> editor
- Video editor: drag-drop upload, file picker, YouTube URL probe (ETA + 5분 경고),
  background yt-dlp download with progress polling, navbar title edit, trim controls,
  save runs ffmpeg trim (original preserved)
- Filesystem storage under data/folders/<name>/<videoId>/{meta.json, original.<ext>, edited.<ext>}

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/routes/public.ts

@@ -0,0 +1,94 @@
+import { Router } from 'express'
+import path from 'node:path'
+import { promises as fs } from 'node:fs'
+import {
+  findVideoAnywhere,
+  folderPath,
+  listFolders,
+  listVideos,
+  loadVideoMeta,
+  sanitizeFolderName,
+  videoDir,
+  videoFileFsPath
+} from '../store.js'
+
+export const publicRouter = Router()
+
+publicRouter.get('/', async (_req, res, next) => {
+  try {
+    const folders = await listFolders()
+    res.render('index', { folders })
+  } catch (err) {
+    next(err)
+  }
+})
+
+publicRouter.get('/folder/:name', async (req, res, next) => {
+  try {
+    const safe = sanitizeFolderName(req.params.name)
+    if (!safe) {
+      res.status(404).send('폴더를 찾을 수 없습니다.')
+      return
+    }
+    // 존재 확인
+    try {
+      await fs.access(folderPath(safe))
+    } catch {
+      res.status(404).send('폴더를 찾을 수 없습니다.')
+      return
+    }
+    const videos = await listVideos(safe)
+    res.render('folder', { folder: safe, videos, isAdmin: false })
+  } catch (err) {
+    next(err)
+  }
+})
+
+publicRouter.get('/player/:videoId', async (req, res, next) => {
+  try {
+    const found = await findVideoAnywhere(req.params.videoId)
+    if (!found) {
+      res.status(404).send('영상을 찾을 수 없습니다.')
+      return
+    }
+    res.render('player', { folder: found.folder, video: found.meta })
+  } catch (err) {
+    next(err)
+  }
+})
+
+/** 영상 파일 스트리밍. ?edited=1 이면 편집본을, 아니면 원본을 보낸다. */
+publicRouter.get('/api/video/:videoId/file', async (req, res, next) => {
+  try {
+    const found = await findVideoAnywhere(req.params.videoId)
+    if (!found) {
+      res.status(404).end()
+      return
+    }
+    const wantEdited = req.query.edited === '1' || req.query.edited === 'true'
+    const fileName =
+      wantEdited && found.meta.editedFile ? found.meta.editedFile : found.meta.originalFile
+    if (!fileName || fileName.includes('%(ext)s')) {
+      res.status(404).end()
+      return
+    }
+    const fsPath = videoFileFsPath(found.folder, found.meta.id, fileName)
+    res.sendFile(fsPath)
+  } catch (err) {
+    next(err)
+  }
+})
+
+/** 비디오 메타 조회 (플레이어/관리자 양쪽에서 사용) */
+publicRouter.get('/api/video/:videoId', async (req, res, next) => {
+  try {
+    const found = await findVideoAnywhere(req.params.videoId)
+    if (!found) {
+      res.status(404).json({ ok: false, message: '영상을 찾을 수 없습니다.' })
+      return
+    }
+    res.json({ ok: true, folder: found.folder, video: found.meta })
+  } catch (err) {
+    next(err)
+  }
+})