Improve install section: direct download link for Windows, simplify macOS

- Windows: clickable download link instead of just filename
- macOS: one-liner curl command
- Quick Start: separate Windows PowerShell and macOS examples

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

README.md

@@ -120,26 +120,26 @@ Groq 免费额度用完 → 自动切到 Cerebras → 再切 SambaNova。**你
 
 ## 安装
 
-```powershell
-# Windows — 下载后双击运行
-.\openrelay-windows-x64.exe
-```
+**Windows**：[点击下载 openrelay-windows-x64.exe](https://github.com/romgX/openrelay/releases/latest/download/openrelay-windows-x64.exe)，下载后双击运行。
 
+**macOS**：
 ```bash
-# macOS（Apple Silicon）下载二进制（无需 Node.js）
-curl -L -o openrelay https://github.com/romgX/openrelay/releases/latest/download/openrelay-macos-arm64
-chmod +x openrelay
-xattr -d com.apple.quarantine openrelay   # 仅首次需要
-./openrelay
+curl -L -o openrelay https://github.com/romgX/openrelay/releases/latest/download/openrelay-macos-arm64 && chmod +x openrelay && ./openrelay
 ```
 
-
 ## 快速上手
 
+```powershell
+# Windows (PowerShell)
+.\openrelay-windows-x64.exe              # 启动
+.\openrelay-windows-x64.exe --test       # 测试所有 Provider 连接
+```
+
 ```bash
-openrelay           # 启动代理
-openrelay --setup   # macOS 首次运行：授权 Keychain
-openrelay --test    # 测试所有 Provider 连接
+# macOS
+./openrelay                # 启动
+./openrelay --setup        # 首次运行：授权 Keychain
+./openrelay --test         # 测试所有 Provider 连接
 ```
 
 浏览器打开 `http://localhost:18765` — 一切在 Web 面板中管理，支持中英双语。
@@ -324,30 +324,26 @@ When Groq's free quota runs out → automatic failover to Cerebras → then Samb
 
 ## Install
 
-### Binary (recommended, no Node.js needed)
-
-Download from [GitHub Releases](https://github.com/romgX/openrelay/releases):
-
-```powershell
-# Windows
-.\openrelay-windows-x64.exe
-```
+**Windows**: [Download openrelay-windows-x64.exe](https://github.com/romgX/openrelay/releases/latest/download/openrelay-windows-x64.exe), double-click to run.
 
+**macOS**:
 ```bash
-# macOS (Apple Silicon)
-curl -L -o openrelay https://github.com/romgX/openrelay/releases/latest/download/openrelay-macos-arm64
-chmod +x openrelay
-xattr -d com.apple.quarantine openrelay   # first time only
-./openrelay
+curl -L -o openrelay https://github.com/romgX/openrelay/releases/latest/download/openrelay-macos-arm64 && chmod +x openrelay && ./openrelay
 ```
 
-
 ## Quick Start
 
+```powershell
+# Windows (PowerShell)
+.\openrelay-windows-x64.exe              # Start
+.\openrelay-windows-x64.exe --test       # Test all provider connections
+```
+
 ```bash
-openrelay                # Start the proxy
-openrelay --setup        # First time on macOS: authorize Keychain
-openrelay --test         # Test all provider connections
+# macOS
+./openrelay                # Start
+./openrelay --setup        # First time: authorize Keychain
+./openrelay --test         # Test all provider connections
 ```
 
 Open `http://localhost:18765` → everything is managed from the Web dashboard.