plan(m0): check release installs in CI before release-proof

[kixelated]

Summary

#24 merged the cargo-dist release workflow, but nothing has been checked against a real release yet. This PR plans that check.

• New [S] quest, quest/m0/install-check.md. It adds a reusable workflow that dist runs after every release through post-announce-jobs. The workflow installs the tag through mise's github: backend and through quest-installer.sh on all four targets, then checks quest --version.
• release-proof now requires the install check. It also records that there's no rc tag: v0.1.0's run gates the quest, and a broken install ships as a fixed v0.1.x.

Decisions

Review for #24

• ✅ Count the takeover review (recommended)
• Run /code-review first
• The user reviews it

Release smoke test

• Tag an rc after merge (recommended)
• ✅ Fold it into release-proof
• Skip it

Goal: release-proof is only done once v0.1.0's published release installs a working quest through both mise and quest-installer.sh on macOS and Linux. A broken install ships as a fixed v0.1.x.

• ✅ Confirm (recommended)
• Only mise
• Only one OS

Method

• ✅ dist post-announce job (recommended)
• By hand once
• Manual dispatch only

A separate release: published trigger won't work: dist creates the release with GITHUB_TOKEN, and events made with that token don't start other workflows.

Split

• ✅ Separate [S] quest (recommended)
• Inside release-proof

Platforms

• ✅ All four targets (recommended)
• One per OS

Validation

• quest check passes (9 documents).

🤖 Generated with Claude Code

(written by Claude Opus 5.5)