chore: apply unreleased upstream improvements from caffeinelabs/motoko#6083 and caffeinelabs/mops#530

[marc0olo]

Context

PR #183 introduced the motoko, mops-cli, and migration skills. During review, we submitted feedback to the upstream repos. Two upstream PRs landed in response — both on main/master but not yet on a release tag. Our sync workflow (sync-upstream.yml) only watches releases, so these won't be auto-detected until upstream cuts a new release.

This issue tracks the follow-up work to apply those improvements proactively and clean up the ownership comment.

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Tasks

1. Trim the "Sections owned by icskills" comment in skills/motoko/SKILL.md

The upstream PR caffeinelabs/motoko#6083 absorbed our contributions, so several sections are no longer icskills-exclusive. The ownership comment should only list what's truly unique to icskills:

Remove from the owned list (now also in upstream):

• transient var
• M0141
• variant tag

Keep in the owned list (still icskills-only):

• Runtime.envVar
• icp-cli deployment notes
• M0145
• Cross-reference links to other icskills skills (Load motoko skill, Load mops-cli skill)
• References owned by icskills line (references/examples.md, references/control-flow.md, references/type-conversions.md)

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2. Add content from caffeinelabs/motoko#6083 that we don't have yet

caffeinelabs/motoko#6083 added:

• Reserved keywords list (53 reserved words) to writing-motoko/SKILL.md — add this to skills/motoko/SKILL.md
• Field-initializer constraint note to writing-motoko/examples.md — add to skills/motoko/references/examples.md

Fetch the exact content from the upstream PR to apply it accurately:

# Get the unreleased commit SHA for the writing-motoko changes
# The PR was merged into caffeinelabs/motoko main — fetch the current main tip
curl -s "https://api.github.com/repos/caffeinelabs/motoko/git/ref/heads/main" | python3 -c "import sys,json; print(json.load(sys.stdin)['object']['sha'])"

# Then fetch the skill file at that SHA
curl -s "https://raw.githubusercontent.com/caffeinelabs/motoko/<sha>/.agents/skills/writing-motoko/SKILL.md"

When updating the upstream comment block in skills/motoko/SKILL.md, note the commit SHA from the merged PR (not a release tag). Use the format:

<!-- Upstream: https://github.com/caffeinelabs/motoko
     Tag: 1.7.0  Commit: <new-sha-from-main>
     ...
     Last synced: <today> -->

Since this is a pre-release sync, the tag stays 1.7.0 (the last released tag) and the commit SHA updates to the main tip.

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3. Apply improvements from caffeinelabs/mops#530 to skills/mops-cli/SKILL.md

caffeinelabs/mops#530 made these changes to .agents/skills/mops-cli/SKILL.md:

• Mark as experimental: mops migrate, next directory field in mops.toml, and build-limit field
• Simplify recommended workflow: The recommended [canisters.backend.migrations] block should show only chain + optional check-limit. Remove build-limit and next from the recommended example (they're experimental).
• Version bumps in example mops.toml / config blocks:
  • moc: 1.5.1 → 1.7.0
  • lintoko: 0.9.0 → 0.10.0
  • core: 2.2.0 → 2.5.0

Fetch the exact diff:

# Get current main SHA for caffeinelabs/mops
curl -s "https://api.github.com/repos/caffeinelabs/mops/git/ref/heads/main" | python3 -c "import sys,json; print(json.load(sys.stdin)['object']['sha'])"

# Fetch the skill file at that SHA
curl -s "https://raw.githubusercontent.com/caffeinelabs/mops/<sha>/.agents/skills/mops-cli/SKILL.md"

Update the upstream comment in skills/mops-cli/SKILL.md similarly: keep Tag: cli-v2.13.1, update commit SHA to the current main tip, update Last synced date.

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4. Validate and open a PR

npm run validate

Fix any errors. Open a PR targeting main with:

• Title: chore: sync upstream improvements from caffeinelabs/motoko#6083 and mops#530
• Reference this issue

No eval results are required since no new pitfalls or behaviors are being added — only existing content from upstream + trimming the ownership comment.

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Going forward

Once this PR merges, the next time upstream cuts a release:

• sync-upstream.yml will fire and open a sync PR
• The diff will be small (most content already aligned)
• The ownership comment accurately reflects what to protect

No action needed from this issue beyond the tasks above.