feat: add Skill Hub feature for managing community skills

- Implemented Skill Hub page with tabs for remote, local, and installed skills.
- Added localization support for Chinese in skill-hub.json.
- Created API routes for fetching remote skills, listing local skills, and managing installed skills.
- Developed functionality for installing and uninstalling skills from both remote and local sources.
- Introduced caching mechanism for remote skills and handling updates for installed skills.

ccw/frontend/src/pages/index.ts

@@ -36,3 +36,4 @@ export { CliSessionSharePage } from './CliSessionSharePage';
 export { IssueManagerPage } from './IssueManagerPage';
 export { TeamPage } from './TeamPage';
 export { TerminalDashboardPage } from './TerminalDashboardPage';
+export { SkillHubPage } from './SkillHubPage';