docs(community): add Xenon Skill and MCP interoperability guide

[xianyu-sheng]

Summary

• add Chinese and English community documentation for reusing VeADK-compatible SKILL.md directories and stdio MCP servers in Xenon
• use the existing examples/codex_with_skill_and_mcp weather example for executable setup and verification commands
• document the component mapping and explicitly state that this does not add Agent(runtime="xenon") support
• target the published Xenon v0.7.1 release, which contains the documented integration CLI

Validation

• fumadocs-mdx, next typegen, and tsc --noEmit passed
• Xenon v0.7.1 wheel and sdist passed Twine checks; isolated wheel install reports runtime and distribution version 0.7.1
• full static site build passed: 288/288 pages generated
• both /cn/docs/framework/community/xenon/ and /en/docs/framework/community/xenon/ HTML outputs generated
• bilingual structure check: 3 headings, 6 code blocks, and 2 callouts per page; navigation order matches
• real MCP interoperability check using the repository weather server (mcp==1.26.0): initialize + tools/list + get_weather succeeded, 1 server / 1 tool, about 480 ms

中文说明

本 PR 增加 Xenon 与 VeADK 在标准 Skill/MCP 组件层的双语互操作指南，并清楚区分“组件复用”和“VeADK 原生 Xenon runtime 适配”，避免夸大当前集成范围。