Add Skill Hub — 5,200+ AI Agent Skills directory

[rdone4425]

Skill Hub (https://skill.442595.xyz/) is an open-source directory of 5,200+ AI Agent Skills across 22 categories. It provides full-text search, category filtering, platform filtering (Claude Code, Codex, Cursor, Hermes, OpenCode), bilingual CN/EN support, and daily GitHub auto-sync.

Stats: 5,231+ skills, 22 categories, 50+ platforms

[github-actions]

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