refactor(skills): optimize skill structure for better performance

[jackwener]

Summary

• Root SKILL.md 从 879 行精简到 120 行（-86% context consumption），大幅减少每次触发时的 token 消耗
• 完整命令参考提取到 references/commands.md，按需加载而非全量注入
• 新增 adapter-dev skill — adapter 开发指南（YAML/TS 模板、pipeline steps、验证清单）
• 新增 record-workflow skill — opencli record 工作流（录制、候选 YAML 生成、TS 转换）
• 优化 cross-project-adapter-migration 和 review-pr 的 description，提升触发精度

Before/After

文件	Before	After	Change
Root SKILL.md	879 lines	120 lines	-86%
references/commands.md	—	487 lines	new (on-demand)
adapter-dev	—	162 lines	new skill
record-workflow	—	109 lines	new skill

Test plan

• opencli list still works correctly
• Skills trigger on expected prompts (e.g. "create adapter for X", "record API calls")
• Root SKILL.md provides correct index to sub-skills