Perf: Optimize macOS screen capture with CGDisplayStream

Core optimization:
- Use CGDisplayStream instead of per-frame CGDisplayCreateImage
- Push model: CPU sleeps when screen is static (condition_variable wait)
- IOSurface capture avoids expensive image creation per frame
- ~47% CPU reduction during active remote desktop (45% → 24%)

Additional optimizations:
- vImageVerticalReflect (SIMD) replaces manual row-by-row flip
- Cache CGColorSpaceRef to avoid per-frame creation/release
- Cache tempBuffer to avoid per-frame memory allocation
- Throttle getCursorTypeIndex to 250ms (Accessibility API is expensive)

Bug fixes:
- Fix unreliable screen capture permission check (use actual capture test)
- Improve permission logging

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

macos/install.sh

@@ -0,0 +1,103 @@
+#!/bin/bash
+# macOS Ghost Client 安装脚本
+# 用法: ./install.sh [ghost路径]
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+GHOST_SRC="${1:-$SCRIPT_DIR/build/bin/ghost}"
+GHOST_DST="/usr/local/bin/ghost"
+PLIST_DST="/Library/LaunchDaemons/com.ghost.client.plist"
+
+echo "=== Ghost Client 安装程序 ==="
+echo "源文件: $GHOST_SRC"
+
+# 检查源文件
+if [ ! -f "$GHOST_SRC" ]; then
+    echo ""
+    echo "错误: 找不到 $GHOST_SRC"
+    echo ""
+    echo "请先编译: ./build.sh"
+    echo ""
+    echo "或指定路径: $0 <ghost可执行文件路径>"
+    exit 1
+fi
+
+set -e
+
+# 1. 停止旧服务（只停止安装目录的，不影响调试目录）
+echo "[1/6] 停止旧服务..."
+sudo launchctl unload "$PLIST_DST" 2>/dev/null || true
+sudo pkill -9 -f "$GHOST_DST" 2>/dev/null || true
+
+# 2. 复制程序
+echo "[2/6] 安装程序到 $GHOST_DST..."
+sudo cp "$GHOST_SRC" "$GHOST_DST"
+sudo chmod +x "$GHOST_DST"
+
+# 3. 清除隔离属性
+echo "[3/6] 清除隔离属性..."
+sudo xattr -cr "$GHOST_DST"
+
+# 4. 签名
+echo "[4/6] 签名程序..."
+sudo codesign --force --deep --sign - "$GHOST_DST"
+
+# 5. 创建 launchd plist
+echo "[5/6] 创建 launchd 服务..."
+sudo tee "$PLIST_DST" > /dev/null << 'EOF'
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+    <key>Label</key>
+    <string>com.ghost.client</string>
+
+    <key>ProgramArguments</key>
+    <array>
+        <string>/usr/local/bin/ghost</string>
+    </array>
+
+    <key>RunAtLoad</key>
+    <true/>
+
+    <key>KeepAlive</key>
+    <true/>
+
+    <key>StandardOutPath</key>
+    <string>/var/log/ghost.log</string>
+
+    <key>StandardErrorPath</key>
+    <string>/var/log/ghost.log</string>
+</dict>
+</plist>
+EOF
+
+sudo chown root:wheel "$PLIST_DST"
+sudo chmod 644 "$PLIST_DST"
+
+# 6. 完成
+echo "[6/6] 安装完成!"
+echo ""
+echo "========================================"
+echo "重要: 首次运行需要授权系统权限"
+echo "========================================"
+echo ""
+echo "请执行以下步骤:"
+echo ""
+echo "1. 手动运行以触发权限请求:"
+echo "   $GHOST_DST"
+echo ""
+echo "2. 授权后按 Ctrl+C 停止程序（权限需重启生效）"
+echo ""
+echo "3. 启动服务:"
+echo "   sudo launchctl load $PLIST_DST"
+echo ""
+echo "如未弹出授权对话框，手动添加:"
+echo "   系统设置 > 隐私与安全性 > 屏幕录制 > 添加 ghost"
+echo "   系统设置 > 隐私与安全性 > 辅助功能 > 添加 ghost"
+echo ""
+echo "常用命令:"
+echo "  启动: sudo launchctl start com.ghost.client"
+echo "  停止: sudo launchctl stop com.ghost.client"
+echo "  卸载: sudo launchctl unload $PLIST_DST"
+echo "  日志: tail -f /var/log/ghost.log"
+echo ""