[BUG] effort: frontmatter silently ignored in commands/*.md slash commands (works in skills/SKILL.md)

Summary

The effort: frontmatter field is honored for skills/<name>/SKILL.md (and agents) but silently ignored for slash commands defined under commands/<name>.md. Both define /<name>, so the inconsistency is surprising — and effort: is not documented for either path.

Environment

Claude Code v2.1.154 · Opus 4.8 (defaults to high effort) · Windows 11

Repro

1. Create ~/.claude/commands/changelog.md:

``yaml
---
description: "Generate release notes from git log"
keep-coding-instructions: true
effort: medium
---
...
``

1. Start a fresh session and run /changelog in a git repo.
2. Observed: the command runs at high effort. Expected: medium.

Evidence (it's real behavior, not just a status-bar display glitch)

• The live process indicator showed still thinking with high effort for 16s+ (~36s total, ~1.4k thinking tokens) — i.e. the model actually reasoned at high effort, not merely a wrong label.
• The same effort: field does work in skills/<name>/SKILL.md (verified with one skill at effort: high and another at effort: medium).
• The CHANGELOG only ever mentions "effort level applied by skill/agent effort: frontmatter" — never "command".
• The official slash-commands frontmatter reference does not list effort at all (only name, description, disable-model-invocation, allowed-tools, arguments).

Workaround

Manually run /effort medium before invoking and /effort high after. Works, but defeats per-command automation (the whole point of the frontmatter field).

Ask

Either:

• (a) honor effort: in commands/*.md the same way skills/SKILL.md does, or
• (b) if the legacy commands/ format intentionally does not support it, document that explicitly (and document effort: for skills/SKILL.md, since it isn't listed in the frontmatter reference today).

A load-time warning for an unrecognized/ignored frontmatter field would also make this much easier to diagnose — right now it fails silently.