Refactor project name from "Open Claude Design" to "Open Design" (#1)

* Refactor project name from "Open Claude Design" to "Open Design"

- Updated project name in package.json, package-lock.json, and README files.
- Changed CLI commands and references from "ocd" to "od".
- Adjusted file structure references in documentation and code to reflect new naming conventions.
- Enhanced .gitignore to include new runtime data files.
- Updated metadata in LICENSE file to match new project name.

* Add contributing guidelines in English and Chinese

- Introduced CONTRIBUTING.md and CONTRIBUTING.zh-CN.md to provide clear instructions for contributors.
- Outlined contribution types, local setup instructions, and merging criteria for skills and design systems.
- Enhanced README files to reference the new contributing guidelines.

.gitignore

@@ -3,7 +3,16 @@ dist
 .DS_Store
 *.log
 .vite
+
+# Local runtime data — auto-created by the daemon on first start.
+# Holds app.sqlite (project metadata), projects/<id>/ (per-project artifacts,
+# the agent's CWD), and artifacts/ (one-off renders). Never commit.
+.od
+
+# Legacy folder name from before the rename; keep ignored so existing
+# clones don't accidentally stage stale runtime data.
 .ocd
+
 tsconfig.tsbuildinfo
 
 .claude-sessions/*