refactor: 重构 handleChatCompletions 函数模块化

- 使用策略模式处理不同后端(Claude/OpenAI/Gemini)
- 添加 OpenAI chat/completions 兼容支持
- 修复代码缩进符合 ESLint 规范

src/validators/clients/codexCliValidator.js

@@ -53,7 +53,8 @@ class CodexCliValidator {
       // 2. 对于特定路径，进行额外的严格验证
       // 对于 /openai 和 /azure 路径需要完整验证
       const strictValidationPaths = ['/openai', '/azure']
-      const needsStrictValidation = req.path && strictValidationPaths.some(path => req.path.startsWith(path))
+      const needsStrictValidation =
+        req.path && strictValidationPaths.some((path) => req.path.startsWith(path))
 
       if (!needsStrictValidation) {
         // 其他路径，只要 User-Agent 匹配就认为是 Codex CLI

src/validators/clients/geminiCliValidator.js

@@ -55,7 +55,9 @@ class GeminiCliValidator {
         // 包含 generateContent 的路径需要验证 User-Agent
         const geminiCliPattern = /^GeminiCLI\/v?[\d\.]+/i
         if (!geminiCliPattern.test(userAgent)) {
-          logger.debug(`Gemini CLI validation failed - UA mismatch for generateContent: ${userAgent}`)
+          logger.debug(
+            `Gemini CLI validation failed - UA mismatch for generateContent: ${userAgent}`
+          )
           return false
         }
       }