Initial commit: audio2text 双语字幕生成服务

- 音频/视频转双语(英/中)SRT 字幕，Docker 容器化，CPU 开发/GPU 生产同一份代码
- faster-whisper ASR(词级时间戳) + 断句时间戳重算 + NLLB 翻译(模型不共驻)
- 分片上传(断点续传) + SQLite 持久化 + 主页/历史/日志页面
- 历史页文件名搜索；缓存定时清理(默认保留7天，可配置)
- 双 Dockerfile(cpu/gpu) + setup/start/stop 脚本

app/security.py

@@ -0,0 +1,27 @@
+"""/docs Basic Auth：对齐 server/security.py。明文密码，常量时间比较。"""
+
+from __future__ import annotations
+
+import secrets
+
+from fastapi import Depends, HTTPException, status
+from fastapi.security import HTTPBasic, HTTPBasicCredentials
+
+from .config import get_settings
+
+security = HTTPBasic()
+
+
+def require_docs_auth(credentials: HTTPBasicCredentials = Depends(security)) -> str:
+    s = get_settings()
+    if not s.docs.enabled or not s.docs.password:
+        raise HTTPException(status_code=status.HTTP_503_SERVICE_UNAVAILABLE, detail="docs disabled")
+    ok_user = secrets.compare_digest(credentials.username.encode(), s.docs.username.encode())
+    ok_pass = secrets.compare_digest(credentials.password.encode(), s.docs.password.encode())
+    if not (ok_user and ok_pass):
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="invalid credentials",
+            headers={"WWW-Authenticate": f'Basic realm="{s.docs.realm}"'},
+        )
+    return credentials.username