Add skills library and plugin configs for Claude, Cursor, Codex, and OpenCode

- Add frontend-dev, fullstack-dev, and android-native-dev skills
- Add plugin configs for Claude Code, Cursor, Codex, and OpenCode
- Add English and Chinese READMEs with installation instructions
- Add .gitignore

.gitignore

@@ -0,0 +1,25 @@
+# Python
+__pycache__/
+*.py[cod]
+*.egg-info/
+dist/
+build/
+venv/
+.venv/
+
+# Environment
+.env
+.env.local
+
+# OS
+.DS_Store
+Thumbs.db
+
+# IDE
+.idea/
+.vscode/
+*.swp
+*.swo
+
+# Node (opencode plugin)
+node_modules/