优化字幕检测算法、添加多语言翻译支持

- 自适应采样间隔：根据视频帧率调整（60fps+→4, 30fps+→3, 低帧率→2）
- filter_and_merge_intervals 复杂度从 O(n²) 优化为 O(n log n)
- detect_subtitle 区域过滤：单区域快速路径，多区域匹配即停
- 插值逻辑改用 zip 预计算 max_gap，更高效
- SubtitleDetectMode 枚举值改为英文key，通过翻译系统显示本地化名称
- 7种语言文件添加 SubtitleDetectMode 翻译（中/繁/英/日/韩/越/西）
- 旧配置值自动迁移兼容

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

backend/interface/ch.ini

@@ -125,6 +125,10 @@ LAMA = LAMA
 ProPainter = ProPainter
 OpenCV = OpenCV
 
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = 快速
+PP_OCRv5_SERVER = 精准
+
 [InterfaceLanguage]
 ChineseSimplified = 简体中文
 ChineseTraditional = 繁體中文

backend/interface/chinese_cht.ini

@@ -123,7 +123,11 @@ SttnAuto = STTN智慧擦除
 SttnDet = STTN字幕檢測  
 LAMA = LAMA  
 ProPainter = ProPainter  
-OpenCV = OpenCV  
+OpenCV = OpenCV
+
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = 快速
+PP_OCRv5_SERVER = 精準
 
 [InterfaceLanguage]  
 ChineseSimplified = 简体中文  

backend/interface/en.ini

@@ -118,12 +118,16 @@ TargetFileNotFound = Output file not generated. Wait for completion.
 VersionInfo = Current: {} Latest: {}  
 RequestError = Failed to access {}. Reason: {}  
 
-[InpaintMode]  
-SttnAuto = STTN Smart Erase  
-SttnDet = STTN Detection  
-LAMA = LAMA  
-ProPainter = ProPainter  
-OpenCV = OpenCV  
+[InpaintMode]
+SttnAuto = STTN Smart Erase
+SttnDet = STTN Detection
+LAMA = LAMA
+ProPainter = ProPainter
+OpenCV = OpenCV
+
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = Fast
+PP_OCRv5_SERVER = Precise
 
 [InterfaceLanguage]  
 ChineseSimplified = 简体中文  

backend/interface/es.ini

@@ -123,7 +123,11 @@ SttnAuto = STTN borrado inteligente
 SttnDet = STTN detección  
 LAMA = LAMA  
 ProPainter = ProPainter  
-OpenCV = OpenCV  
+OpenCV = OpenCV
+
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = Rápido
+PP_OCRv5_SERVER = Preciso
 
 [InterfaceLanguage]  
 ChineseSimplified = 简体中文  

backend/interface/japan.ini

@@ -125,6 +125,10 @@ LAMA = LAMA
 ProPainter = ProPainter
 OpenCV = OpenCV
 
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = 高速
+PP_OCRv5_SERVER = 高精度
+
 [InterfaceLanguage]
 ChineseSimplified = 简体中文
 ChineseTraditional = 繁體中文

backend/interface/ko.ini

@@ -125,6 +125,10 @@ LAMA = LAMA
 ProPainter = ProPainter
 OpenCV = OpenCV
 
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = 빠른
+PP_OCRv5_SERVER = 정밀
+
 [InterfaceLanguage]
 ChineseSimplified = 简体中文
 ChineseTraditional = 繁體中文

backend/interface/vi.ini

@@ -125,6 +125,10 @@ LAMA = LAMA
 ProPainter = ProPainter
 OpenCV = OpenCV
 
+[SubtitleDetectMode]
+PP_OCRv5_MOBILE = Nhanh
+PP_OCRv5_SERVER = Chính xác
+
 [InterfaceLanguage]
 ChineseSimplified = 简体中文
 ChineseTraditional = 繁體中文