fix(openclaw): use sync plugin registration

[kesslerio]

What

• make the generated OpenClaw plugin entrypoint export a synchronous register(api) function
• inline converted command bodies into the generated command handlers
• remove async skill preloading from the generated OpenClaw entrypoint

Why

• OpenClaw ignores plugin registrations that return a promise
• the generated async entrypoint causes the runtime to report: plugin register returned a promise; async registration is ignored
• switching to fire-and-forget skill loading fixes the warning but introduces a startup race where commands can return not found before skill files finish loading
• inlining the converted command body removes both issues and keeps registration synchronous

Tests

• bun test tests/openclaw-converter.test.ts

AI Assistance

• Used: yes
• Testing: targeted automated test (bun test tests/openclaw-converter.test.ts) plus local OpenClaw plugin inspection after reinstall