chore: Add THIRD_PARTY_NOTICES.md for vendored third-party code (#5186)

* chore: Add THIRD_PARTY_NOTICES.md for vendored third-party code

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* chore: Add changelog entry for THIRD_PARTY_NOTICES.md

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix changelog section name

* Update CHANGELOG.md

Co-authored-by: Roman Zavarnitsyn <rom4ek93@gmail.com>

* chore: Bundle THIRD_PARTY_NOTICES.md in sentry JAR under META-INF

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

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Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: Roman Zavarnitsyn <rom4ek93@gmail.com>