feat(cli): prioritize GitHub release download with fallback to bundled assets (#81)

- Add GitHubRateLimitError and GitHubDownloadError for better error handling
- Detect rate limits (403 with remaining=0, 429)
- Try downloading from GitHub releases first
- Fall back to bundled assets on network error, rate limit, or download failure
- Add --offline flag to skip GitHub download
- Use GitHub auto-generated archive URL as fallback when no ZIP asset exists
- Update CLI to v1.9.0

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "uipro-cli",
-  "version": "1.8.0",
+  "version": "1.9.0",
   "description": "CLI to install UI/UX Pro Max skill for AI coding assistants",
   "type": "module",
   "bin": {