ci: 添加 aether-proxy 多平台自动编译与 README 文档

- 新增 GitHub Actions workflow，推送 proxy-v* tag 自动编译 5 个平台
  (linux-amd64, linux-arm64, macos-amd64, macos-arm64, windows-amd64)
- 编译产物自动发布到 GitHub Releases 并生成 SHA256 校验文件
- 新增 aether-proxy README，包含部署、配置、后台运行等完整说明

.github/workflows/build-proxy.yml

@@ -0,0 +1,150 @@
+name: Build aether-proxy Binaries
+
+on:
+  push:
+    tags: ['proxy-v*']
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+jobs:
+  build:
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: linux-amd64
+            target: x86_64-unknown-linux-gnu
+            os: ubuntu-latest
+            use_cross: true
+          - name: linux-arm64
+            target: aarch64-unknown-linux-gnu
+            os: ubuntu-latest
+            use_cross: true
+          - name: macos-amd64
+            target: x86_64-apple-darwin
+            os: macos-13
+            use_cross: false
+          - name: macos-arm64
+            target: aarch64-apple-darwin
+            os: macos-latest
+            use_cross: false
+          - name: windows-amd64
+            target: x86_64-pc-windows-msvc
+            os: windows-latest
+            use_cross: false
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install Rust toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: ${{ matrix.target }}
+
+      - name: Rust cache
+        uses: Swatinem/rust-cache@v2
+        with:
+          workspaces: aether-proxy -> target
+          key: ${{ matrix.target }}
+
+      - name: Install cross
+        if: matrix.use_cross
+        uses: taiki-e/install-action@cross
+
+      - name: Build
+        working-directory: aether-proxy
+        shell: bash
+        run: |
+          if [ "${{ matrix.use_cross }}" = "true" ]; then
+            cross build --release --target ${{ matrix.target }}
+          else
+            cargo build --release --target ${{ matrix.target }}
+          fi
+
+      - name: Package (Unix)
+        if: runner.os != 'Windows'
+        shell: bash
+        run: |
+          cd aether-proxy/target/${{ matrix.target }}/release
+          chmod +x aether-proxy
+          tar czf ../../../../aether-proxy-${{ matrix.name }}.tar.gz aether-proxy
+
+      - name: Package (Windows)
+        if: runner.os == 'Windows'
+        shell: bash
+        run: |
+          cd aether-proxy/target/${{ matrix.target }}/release
+          7z a ../../../../aether-proxy-${{ matrix.name }}.zip aether-proxy.exe
+
+      - name: Upload artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: aether-proxy-${{ matrix.name }}
+          path: |
+            aether-proxy-*.tar.gz
+            aether-proxy-*.zip
+          if-no-files-found: error
+
+  release:
+    needs: build
+    runs-on: ubuntu-latest
+    if: startsWith(github.ref, 'refs/tags/')
+    steps:
+      - name: Download all artifacts
+        uses: actions/download-artifact@v4
+        with:
+          merge-multiple: true
+          path: artifacts
+
+      - name: Generate checksums
+        working-directory: artifacts
+        run: sha256sum aether-proxy-* > SHA256SUMS.txt
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          name: "aether-proxy ${{ github.ref_name }}"
+          body: |
+            ## aether-proxy ${{ github.ref_name }}
+
+            ### 下载
+
+            | 平台 | 文件 |
+            |------|------|
+            | Linux x86_64 | `aether-proxy-linux-amd64.tar.gz` |
+            | Linux ARM64 | `aether-proxy-linux-arm64.tar.gz` |
+            | macOS x86_64 (Intel) | `aether-proxy-macos-amd64.tar.gz` |
+            | macOS ARM64 (Apple Silicon) | `aether-proxy-macos-arm64.tar.gz` |
+            | Windows x86_64 | `aether-proxy-windows-amd64.zip` |
+
+            ### 使用
+
+            ```bash
+            # Linux/macOS: 解压
+            tar xzf aether-proxy-<platform>.tar.gz
+
+            # Windows: 解压 zip 文件
+
+            # 配置环境变量 (或写入 .env 文件)
+            export AETHER_PROXY_AETHER_URL=https://your-aether.example.com
+            export AETHER_PROXY_MANAGEMENT_TOKEN=ae_xxx
+            export AETHER_PROXY_HMAC_KEY=your-hmac-key
+
+            # 运行
+            ./aether-proxy
+            ```
+
+            ### 校验
+
+            下载 `SHA256SUMS.txt` 后可验证文件完整性:
+            ```bash
+            sha256sum -c SHA256SUMS.txt
+            ```
+          files: |
+            artifacts/aether-proxy-*
+            artifacts/SHA256SUMS.txt
+          fail_on_unmatched_files: true