chore: prepare the 2.1.4 release

[bagowix]

Summary

Prepare the 2.1.4 patch release.

• bump the package version from 2.1.3 to 2.1.4
• move the current changelog entries from [Unreleased] into 2.1.4
• update changelog comparison links
• update the release version in the comparison page
• regenerate docs/llms-full.txt

Everything in [Unreleased] is infrastructure, documentation and bug fixes —
the correctness docs page, the OpenSSF badge, griffe check, mutation testing,
pyrefly, the Codecov move, the supply-chain hardening, plus the coordinator
lane task_done() fix and EventListener failure isolation. No public symbol
was added or changed, so this is a patch, not a minor.

Why now

The v2.1.4 tag was pushed while interlock/version.py still read 2.1.3, so
the release workflow built 2.1.3 artifacts and PyPI rejected the upload —
that filename already exists and PyPI never allows reuse. The tag has been
deleted locally and on the remote; it needs to be re-created on the merge
commit of this PR so the build picks up the bumped version.

Note on docs/llms-full.txt

The regenerated file carries one change that is not from the version bump:
#87 changed the migration-guide anchors in docs/migration.md but did not
regenerate llms-full.txt, so the committed copy had drifted. Running
scripts/build_llms_full.py brings it back in sync.

docs/comparison.md keeps its "as of July 2026" label: that date records when
the other libraries' versions were checked, and only interlock's own cell
moves — the same way the 2.1.3 release handled it.

The griffe gate had to be fixed first

griffe check failed this PR on Attribute value was changed: '2.1.3' -> '2.1.4'.
The job landed in #118 and this is the first release since, so it had never run
against a version bump — it would have failed every release from now on, or
forced a misleading breaking-change label onto each one.

The -f github run still annotates the diff; the gate now reads a oneline
run with that single finding filtered out. The filter matches only that
attribute, in that file, for that one check, so it fails closed: if griffe
rewords the message it stops matching and the job fails. Verified both ways
locally — the bump alone passes, and a removed public export
(sync_timeout) still fails it.

Checklist

• Test suite passes with 100% coverage (583 passed, 2 skipped)
• uv run ruff format --check and uv run ruff check pass
• uv run mypy, uv run pyright and uv run pyrefly check pass
• Documentation updated (docs/)
• CHANGELOG.md [Unreleased] updated
• Release artifacts build successfully (interlock_cb-2.1.4, sdist + wheel)
• Commits follow Conventional Commits

Related issues

• Includes changes from Isolate EventListener failures from protected application calls #83, Call task_done() when a coordinator lane exits on a collected coordinator #97, Run the test suite on free-threaded CPython (3.14t) #102, Add mutation testing for the state machine and engine #103, Detect public-API breakage with griffe check in CI #104, Harden the CI supply chain: zizmor, SHA-pinned actions, OpenSSF Scorecard #105, Document the correctness and testing strategy, and earn the OpenSSF Best Practices badge #107, ci: add pyrefly and move coverage reporting to Codecov #113, docs: run zensical in strict mode #87

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ All tests successful. No failed tests found.

📢 Thoughts on this report? Let us know!

[codspeed-hq]

Merging this PR will not alter performance

✅ 21 untouched benchmarks

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_{Comparing chore/prepare-2.1.4-release (e9c4506) with main (484118c)}