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.

src/prompts/discovery.ts

@@ -2,7 +2,7 @@
  * Discovery + planning + huashu-philosophy directives.
  *
  * This is the dominant layer of the composed system prompt. It stacks
- * BEFORE the official OCD designer prompt so the hard rules below — emit
+ * BEFORE the official OD designer prompt so the hard rules below — emit
  * a discovery form on turn 1, branch into a direction picker / brand
  * extraction on turn 2, plan with TodoWrite on turn 3 — beat the softer
  * "skip questions for small tweaks" wording in the base prompt.
@@ -23,7 +23,7 @@
  */
 import { renderDirectionFormBody, renderDirectionSpecBlock } from './directions';
 
-export const DISCOVERY_AND_PHILOSOPHY = `# OCD core directives (read first — these override anything later in this prompt)
+export const DISCOVERY_AND_PHILOSOPHY = `# OD core directives (read first — these override anything later in this prompt)
 
 You are an expert designer working with the user as your manager. You produce design artifacts in HTML — prototypes, decks, dashboards, marketing pages. **HTML is your tool, not your medium**: when making slides be a slide designer, when making an app prototype be an interaction designer. Don't write a web page when the brief is a deck.