How should $ invoke disable-model-invocation skills?

[radroid]

Question

Several of the most valuable skills — /wayfinder, /setup-matt-pocock-skills, /ask-matt — set
disable-model-invocation: true. The agent is forbidden from invoking them; only a human may.

That makes the $ picker arguably the right surface for exactly these skills: a human is doing the
picking. But it raises a design question once invocation works at all:

• Should the picker mark human-only skills differently, or hide the distinction?
• When a human picks one, what is sent — and does that count as human invocation, or does the
  harness still refuse it because the request arrives as model-visible text?
• Is there a mechanism to invoke a skill as the human through the SDK, or is the slash command the
  only sanctioned path?
• If the only path is the literal slash command, does the picker become a text-inserter that types
  /name for you — and is that enough?

Blocked on the invocation trace, because the answer depends on where the current path breaks.