Add voice history, default preset voice, and one-click tab

Keep synthesized wav files browsable with playback and download, default to preset steady male voice, show one-click pipeline as the first tab, and reduce post-synthesis UI flicker.

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

voice_history.py

@@ -0,0 +1,51 @@
+"""
+本地配音历史：扫描 outputs/ 下已生成的 wav，供 Gradio 下拉试听与下载。
+文件不会被自动删除，重启服务后仍可访问。
+"""
+
+from __future__ import annotations
+
+import logging
+from datetime import datetime
+from pathlib import Path
+from typing import List, Tuple
+
+from config import OUTPUT_DIR
+
+logger = logging.getLogger(__name__)
+
+HISTORY_MAX_ITEMS = 50
+VOICEOVER_GLOB = "voiceover_*.wav"
+
+
+def list_voice_history(limit: int = HISTORY_MAX_ITEMS) -> List[Tuple[str, str]]:
+    """
+    返回 Gradio Dropdown 选项：(显示名, 文件绝对路径)，按时间倒序。
+    """
+    if not OUTPUT_DIR.is_dir():
+        return []
+
+    files = sorted(
+        OUTPUT_DIR.glob(VOICEOVER_GLOB),
+        key=lambda p: p.stat().st_mtime,
+        reverse=True,
+    )[:limit]
+
+    choices: List[Tuple[str, str]] = []
+    for path in files:
+        try:
+            st = path.stat()
+        except OSError:
+            logger.debug("跳过不可读历史文件: %s", path)
+            continue
+        ts = datetime.fromtimestamp(st.st_mtime).strftime("%Y-%m-%d %H:%M")
+        size_mb = st.st_size / (1024 * 1024)
+        label = f"{ts} · {path.name} ({size_mb:.1f} MB)"
+        choices.append((label, str(path.resolve())))
+    return choices
+
+
+def latest_voice_path() -> str | None:
+    """最新一条配音路径，无历史时返回 None。"""
+    items = list_voice_history(limit=1)
+    return items[0][1] if items else None