Add system architecture diagrams to README files

Introduced detailed system architecture and request processing flow diagrams using Mermaid in the English, Simplified Chinese, and Traditional Chinese README files. These additions provide a clearer overview of the platform's internal structure and request handling logic for developers and users.

README.zh-Hant.md

@@ -138,6 +138,83 @@
 - **下載工具相容性**：完美支援 wget、cURL、aria2、IDM 等主流下載工具
 - **CI/CD 整合**：可直接在 GitHub Actions、GitLab CI 等環境中使用
 
+## 🏗️ 系統架構
+
+### 請求處理流程
+
+```mermaid
+graph TD
+    Request[使用者請求 / User-Agent] --> Identify{識別平台}
+    Identify -->|無效| Error[返回錯誤]
+    Identify -->|有效| Transform[轉換路徑]
+    
+    Transform --> CheckProtocol{檢查協定}
+    
+    CheckProtocol -->|Git| GitHandler[Git 協定適配器]
+    CheckProtocol -->|Docker| DockerHandler[Docker 協定適配器]
+    CheckProtocol -->|AI| AIHandler[AI 推理適配器]
+    CheckProtocol -->|標準| StdHandler[標準適配器]
+    
+    GitHandler --> Upstream[獲取上游]
+    DockerHandler --> Upstream
+    AIHandler --> Upstream
+    
+    StdHandler --> CacheCheck{檢查快取}
+    CacheCheck -->|命中| ReturnCache[返回快取回應]
+    CacheCheck -->|未命中| Upstream
+    
+    Upstream -->|成功| ProcessResponse[處理回應]
+    Upstream -->|失敗| Retry{重試?}
+    
+    Retry -->|是| Wait[等待 (退避)] --> Upstream
+    Retry -->|否| Error
+    
+    ProcessResponse --> Finalize[添加標頭並返回]
+    Finalize --> Response[回應]
+```
+
+### 組件架構
+
+```mermaid
+classDiagram
+    class Worker {
+        +handleRequest(request)
+    }
+    class Config {
+        +PLATFORMS
+        +transformPath()
+    }
+    class Validation {
+        +validateRequest()
+        +isDockerRequest()
+    }
+    class GitProtocol {
+        +configureGitHeaders()
+        +isGitRequest()
+    }
+    class DockerProtocol {
+        +handleDockerAuth()
+        +fetchToken()
+    }
+    class AIProtocol {
+        +configureAIHeaders()
+    }
+    class Security {
+        +addSecurityHeaders()
+    }
+    class Performance {
+        +monitor()
+    }
+
+    Worker --> Config
+    Worker --> Validation
+    Worker --> GitProtocol
+    Worker --> DockerProtocol
+    Worker --> AIProtocol
+    Worker --> Security
+    Worker --> Performance
+```
+
 ## 📖 URL 轉換規則
 
 使用預部署實例 **`xget.xi-xu.me`** 或您自己部署的實例，只需簡單替換網域並新增平台前綴：