Add OMem skill (local work memory for AI agents)

[seacen]

What this adds

Adds OMem (Office Memory) as a community skill, in both English and Chinese:

• src/content/skills/omem.md (English, full frontmatter)
• src/content/skills-zh/omem.md (Chinese body, slug: omem)

What is OMem

OMem is a local-first, agent-neutral work-memory layer. It auto-builds a single
locally-indexed wiki from your emails, calendar, local files (OneDrive / Dropbox /
iCloud Drive / any folder), and collaboration notes — then exposes it to your agent
as read-only context. So the agent answers from your real work history instead of
guessing, and nothing is uploaded to a third-party service.

The skill is a thin read-only wrapper over the local omem CLI (6 read-only ops:
query / page_get / raw_get_path / raw_get_parsed_path / wiki_ls / doctor).
It never ingests, deletes, or reconfigures — those stay user actions.

• Repo: https://github.com/seacen/omem
• Docs: https://seacen.github.io/omem/ · 中文: https://seacen.github.io/omem/zh-cn/

Checklist

• Added under src/content/skills/ and src/content/skills-zh/
• Frontmatter follows _template.md (valid category: productivity)
• Includes Use Cases / Example / Notes sections
• English + Chinese versions
• One skill, focused PR