chore: release 4.0.4

[futamura]

Summary

Prepares the 4.0.4 release. No source changes — a patch bump covering the work merged after 4.0.3.

• MARKETING_VERSION: 4.0.3 → 4.0.4, set with bundle exec fastlane bump_version type:patch.
• CHANGELOG.md: the Unreleased section becomes [4.0.4] - 2026-10-05, with the compare links updated.

Contents of the release:

• The simulator test jobs retry once when xcodebuild aborts with exit code 134 during teardown (Retry the simulator jobs once on exit 134 #96).
• fastlane 2.238.0 → 2.240.1, which pulls in rubyzip 3.7.0 and resolves the Dependabot alert for GHSA-47m2-wp7j-p9vc (chore: bump fastlane to 2.240.1 for rubyzip 3.7.0 #97). Development-only dependency, so it is not in the CHANGELOG. Dependabot only scans main, so the alert closes when this PR merges.

Release steps after merge

Push the bare tag 4.0.4, which release.yml verifies against MARKETING_VERSION before creating the GitHub Release from the CHANGELOG section.

Test plan

• bundle exec fastlane bump_version type:patch set MARKETING_VERSION to 4.0.4; the pbxproj diff touches only those lines.
• bundle exec fastlane lint_swift and bundle exec fastlane build_spm passed locally with the updated bundle.
• CI is the usual lint + per-platform tests.

Part of FUT-44
Part of FUT-255

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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