docs(integrations): add Hermes Agent skill guide

[dongmucat]

Summary

• add Chinese and English integration guides for NousResearch Hermes Agent 0.18.2
• document the verified SkillHub CLI --dir install, discovery, overwrite-update, and removal lifecycle
• define registry, trust, multi-file, normalized command-name, and external-directory safety boundaries
• add same-language Hermes guide links to both project READMEs

Validation

• isolated live install of github/list-skills with SkillHub CLI 0.1.8 into $HERMES_HOME/skills/skillhub/github
• Hermes Agent 0.18.2 skills list, skills_list(), and skill_view() discovery/load checks
• overwrite update with install --force, followed by local removal and inventory/discovery cleanup checks
• make docs-build
• make test-cli — 336 passed
• make test-backend-app — 574 passed in skillhub-app and all dependent modules
• make typecheck-web
• make lint-web
• frontend Vitest with Node 22.12 — 180 files, 609 tests passed (the host Node 20.18 is below the locked jsdom dependency engine floor)
• make staging — 15 smoke tests passed
• git diff --check

Security

This change adds documentation only. The guides explicitly state that Hermes treats SkillHub CLI-installed packages as local skills, so Hermes Hub community-install scanning is not applied, and that format compatibility does not guarantee tool/runtime compatibility.

Closes #582

[FenjuFu]

内容没问题，CI 其余全绿，只差 DCO：commit 需要 Signed-off-by（git rebase --signoff 后 force-push）。