refactor: 简化 ccw 安装流程，移除远程下载功能

- 删除 version-fetcher.js，移除 GitHub API 依赖
- install.js: 移除远程版本选择，只保留本地安装
- upgrade.js: 重写为本地升级，比对包版本与已安装版本
- cli.js: 移除 -v/-t/-b 等版本相关选项
- 添加 CLAUDE.md 复制到 .claude 目录的逻辑

版本管理统一到 npm：npm install -g ccw@版本号

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

ccw/src/cli.js

@@ -74,9 +74,6 @@ export function run(argv) {
     .description('Install Claude Code Workflow to your system')
     .option('-m, --mode <mode>', 'Installation mode: Global or Path')
     .option('-p, --path <path>', 'Installation path (for Path mode)')
-    .option('-v, --version <version>', 'Version type: local, stable, latest, or branch', 'local')
-    .option('-t, --tag <tag>', 'Specific release tag (e.g., v3.2.0) for stable version')
-    .option('-b, --branch <branch>', 'Branch name for branch version type', 'main')
     .option('-f, --force', 'Force installation without prompts')
     .action(installCommand);
 
@@ -89,12 +86,8 @@ export function run(argv) {
   // Upgrade command
   program
     .command('upgrade')
-    .description('Upgrade Claude Code Workflow installations to latest version')
+    .description('Upgrade Claude Code Workflow installations')
     .option('-a, --all', 'Upgrade all installations without prompting')
-    .option('-l, --latest', 'Upgrade to latest development version (main branch)')
-    .option('-t, --tag <tag>', 'Upgrade to specific release tag (e.g., v3.2.0)')
-    .option('-b, --branch <branch>', 'Upgrade to specific branch')
-    .option('-s, --select', 'Force interactive version selection')
     .action(upgradeCommand);
 
   // List command