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.

docs/assets/banner.svg

@@ -0,0 +1,43 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 2400 800" preserveAspectRatio="xMidYMid meet" role="img" aria-label="Hero banner placeholder">
+  <defs>
+    <linearGradient id="bg" x1="0" y1="0" x2="0" y2="1">
+      <stop offset="0%" stop-color="#FBF7EF"/>
+      <stop offset="100%" stop-color="#EFE7D7"/>
+    </linearGradient>
+  </defs>
+  <rect width="2400" height="800" fill="url(#bg)"/>
+  <rect x="32" y="32" width="2336" height="736" rx="28" ry="28"
+    fill="none" stroke="#C2532D" stroke-width="3" stroke-dasharray="16 12" opacity="0.85"/>
+  <g transform="translate(1200 340)" stroke="#1F1B16" stroke-width="6"
+     stroke-linecap="round" stroke-linejoin="round" fill="none" opacity="0.9">
+    <rect x="-110" y="-72" width="220" height="144" rx="18"/>
+    <rect x="-36" y="-94" width="72" height="26" rx="8"/>
+    <circle r="42"/>
+    <circle r="18"/>
+  </g>
+  <text x="1200" y="430" text-anchor="middle"
+        font-family="ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif"
+        font-size="34" font-weight="600" letter-spacing="6" fill="#C2532D">
+    OPEN DESIGN
+  </text>
+  <text x="1200" y="510" text-anchor="middle"
+        font-family="ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif"
+        font-size="56" font-weight="700" fill="#1F1B16">
+    Hero banner
+  </text>
+  <text x="1200" y="575" text-anchor="middle"
+        font-family="ui-monospace, SFMono-Regular, Menlo, Consolas, monospace"
+        font-size="26" fill="#6B6258">
+    docs/assets/banner.svg
+  </text>
+  <text x="1200" y="640" text-anchor="middle"
+        font-family="ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif"
+        font-size="24" fill="#6B6258">
+    Replace with a wide product screenshot or marketing illustration.
+  </text>
+  <text x="1200" y="744" text-anchor="middle"
+        font-family="ui-sans-serif, system-ui, -apple-system, 'Segoe UI', sans-serif"
+        font-size="20" letter-spacing="4" fill="#6B6258" opacity="0.85">
+    SCREENSHOT PENDING · 截图占位
+  </text>
+</svg>