feat: add content filter and code processing module (v0.3.0)

- Add content filter module (internal/content/)
- Implement basic character filtering (control chars, line breaks, symbols)
- Implement code block and inline code detection
- Implement comment detection for 30+ languages (JS/Python/Go/HTML/etc)
- Add go-enry dependency for intelligent language detection
- Add SkipKeywords config option (default: TODO/FIXME/HACK/XXX/etc)
- Integrate content processing into Translator
- Update config.yaml with skip_keywords

internal/config/config.go

@@ -23,6 +23,9 @@ type Config struct {
 
 	// Prompt配置
 	Prompts map[string]string `yaml:"prompts"`
+
+	// 内容过滤配置
+	SkipKeywords []string `yaml:"skip_keywords"` // 不翻译的关键词
 }
 
 // ProviderConfig 厂商配置
@@ -121,6 +124,16 @@ func (c *Config) setDefaults() {
 	if c.Prompts == nil {
 		c.Prompts = make(map[string]string)
 	}
+
+	// 设置默认关键词
+	if c.SkipKeywords == nil {
+		c.SkipKeywords = []string{
+			"TODO", "FIXME", "HACK", "XXX", "NOTE",
+			"BUG", "WARN", "IMPORTANT", "TODO:",
+			"FIXME:", "HACK:", "XXX:", "NOTE:",
+			"BUG:", "WARN:", "IMPORTANT:",
+		}
+	}
 }
 
 // GetProviderConfig 获取指定厂商的配置