`claw skills show <name>`, `claw skills info <name>`, and
`claw skills list <filter>` were all falling through to
SkillSlashDispatch::Invoke, which spawned a real model session,
consumed tokens, and created session files.
Root cause: classify_skills_slash_command had no guards for
these discovery prefixes; every non-reserved arg became Invoke.
Fix:
- Add "show", "info" as Local-only bare tokens
- Add starts_with guards for "show ", "info ", "list " args
- handle_skills_slash_command: filter skill list by name/substring
for show/info/list-filter paths (no model call, no session)
- handle_skills_slash_command_json: same structured filtering
Test: skills_show_and_list_filter_do_not_invoke_model asserts
classify_skills_slash_command returns Local for all discovery
patterns and still returns Invoke for bare skill names.
Pinpoint: ROADMAP #502
94b80a05d3