Add app icon and integrate into build pipeline

- SVG logo design: dark background with chart bars, trend line, dollar
  sign, and "CC" branding representing Claude Code cost monitoring
- Generated .icns from SVG for macOS app bundle icon
- Updated build-app.sh to copy AppIcon.icns and set CFBundleIconFile
- Added icon.png to demos/ for README display
- Updated README with centered logo in header

Author: yishuiliunian

README.md

@@ -1,6 +1,10 @@
-# CCMonitor
+<p align="center">
+  <img src="demos/icon.png" width="128" alt="CCMonitor">
+</p>
+
+<h1 align="center">CCMonitor</h1>
 
-A native macOS menu bar app for real-time monitoring of [Claude Code](https://docs.anthropic.com/en/docs/claude-code) token usage and costs.
+<p align="center">A native macOS menu bar app for real-time monitoring of <a href="https://docs.anthropic.com/en/docs/claude-code">Claude Code</a> token usage and costs.</p>
 
 <p align="center">
   <img src="https://img.shields.io/badge/platform-macOS%2014%2B-blue" alt="Platform">

Sources/CCMonitor/Resources/AppIcon.icns

@@ -38,6 +38,13 @@ if [ -n "$RESOURCE_BUNDLE" ]; then
     echo "  ✅ Copied resource bundle"
 fi
 
+# 复制应用图标
+ICON_FILE="Sources/CCMonitor/Resources/AppIcon.icns"
+if [ -f "$ICON_FILE" ]; then
+    cp "$ICON_FILE" "${APP_DIR}/Contents/Resources/AppIcon.icns"
+    echo "  ✅ Copied app icon"
+fi
+
 # 创建 Info.plist
 cat > "${APP_DIR}/Contents/Info.plist" << 'PLIST'
 <?xml version="1.0" encoding="UTF-8"?>
@@ -64,6 +71,8 @@ cat > "${APP_DIR}/Contents/Info.plist" << 'PLIST'
     <true/>
     <key>NSHighResolutionCapable</key>
     <true/>
+    <key>CFBundleIconFile</key>
+    <string>AppIcon</string>
 </dict>
 </plist>
 PLIST