chore(main): release 0.40.1

[github-actions]

Here's what's new in Charon

0.40.1 (2026-09-08)

Bug Fixes

• ci: restore the toolchain pin to match main's recipe (30f954c)
• ci: restore toolchain pin on main + guard sync-pin-on-pr against protected branches (#1309) (2316e0f)
• ci: stop sync-pin-on-pr from committing to long-lived branches (2e750b4)

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Merge this PR to cut the release.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[github-actions]

✅ Supply Chain Verification Results

✅ PASSED

📦 SBOM Summary

• Components: 1769

🔍 Vulnerability Scan

Severity	Count
🔴 Critical	0
🟠 High	0
🟡 Medium	0
🟢 Low	0
Total	0

📎 Artifacts

• SBOM (CycloneDX JSON) and Grype results available in workflow artifacts

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_{Generated by Supply Chain Verification workflow • View Details}

[github-actions]

🤖 Created releases:

• v0.40.1

🌻