feat: add FFmpeg status check and shutdown button

- FFmpeg check no longer blocks server startup
- Add /api/checkFFmpeg endpoint to query FFmpeg availability
- Add /api/shutdown endpoint to gracefully stop the server
- Add FFmpeg status indicator in web header
- Add shutdown button in web interface
- Move static files output to cmd/bilidown/static for embedding
- Update .gitignore to exclude cmd/bilidown/static

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/header.ts

@@ -1,12 +1,29 @@
 import van from 'vanjs-core'
 import { now } from 'vanjs-router'
-import { GLOBAL_HAS_LOGIN } from './mixin'
+import { GLOBAL_HAS_LOGIN, getApi } from './mixin'
 
-const { a, div } = van.tags
+const { a, div, button, span } = van.tags
+
+export const FFmpegAvailable = van.state<boolean | null>(null)
+
+export const checkFFmpeg = async () => {
+    try {
+        const res = await getApi('/checkFFmpeg')
+        FFmpegAvailable.val = res.data?.available ?? false
+    } catch {
+        FFmpegAvailable.val = false
+    }
+}
 
 export default () => {
     const classStr = (name: string) => van.derive(() => `text-nowrap nav-link ${now.val.split('/')[0] == name ? 'active' : ''}`)
 
+    const shutdown = async () => {
+        if (confirm('确定要关闭服务吗？')) {
+            await getApi('/shutdown')
+        }
+    }
+
     return div({ class: 'hstack gap-4' },
         div({ class: 'fs-4 fw-bold text-nowrap' }, 'Bilidown'),
         div({ class: 'nav nav-underline flex-nowrap overflow-auto' },
@@ -22,6 +39,16 @@ export default () => {
             div({ class: 'nav-item', hidden: GLOBAL_HAS_LOGIN },
                 a({ class: classStr('login'), href: '#/login' }, '扫码登录')
             ),
+        ),
+        div({ class: 'ms-auto hstack gap-2' },
+            // FFmpeg 状态指示器
+            div({ class: 'hstack gap-1' },
+                span({ class: () => `badge ${FFmpegAvailable.val === true ? 'bg-success' : FFmpegAvailable.val === false ? 'bg-danger' : 'bg-secondary'}` },
+                    () => FFmpegAvailable.val === true ? 'FFmpeg ✓' : FFmpegAvailable.val === false ? 'FFmpeg ✗' : '检查中...'
+                )
+            ),
+            // 关闭按钮
+            button({ class: 'btn btn-outline-danger btn-sm', onclick: shutdown }, '关闭服务')
         )
     )
 }

web/src/index.ts

@@ -1,6 +1,6 @@
 /// <reference types="vite/client" />
 import van from 'vanjs-core'
-import Header from './header'
+import Header, { checkFFmpeg } from './header'
 import Work from './work'
 import Task from './task'
 import Login from './login'
@@ -16,6 +16,9 @@ const { div } = van.tags
 
 redirect('home', 'work')
 
+// 启动时检查 FFmpeg 状态
+checkFFmpeg()
+
 van.add(document.body,
     div({ class: 'container py-4 vstack gap-4', hidden: GLOBAL_HIDE_PAGE },
         Header(),

web/src/mixin.ts

@@ -66,4 +66,10 @@ export const formatSeconds = (seconds: number) => {
     if (secs > 0) str += `${secs}秒`
 
     return str
+}
+
+/** API 请求封装 */
+export const getApi = async <T = unknown>(path: string, options?: RequestInit): Promise<ResJSON<T>> => {
+    const res = await fetch('/api' + path, options)
+    return res.json() as Promise<ResJSON<T>>
 }