feat: make errors send and sync

[Vaiz]

Changes

PR updates the return type of a few functions to include Send + Sync + 'static trait bounds on the error type.

It makes error type thread-safe, allowing it to be used in multi-threaded contexts and allows to use this error as a source error for custom error types that are Send and Sync.

The change is more cosmetical, and keeps public API compatible with previous version.

Merge requirement checklist

• CONTRIBUTING guidelines followed
• Unit tests added/updated (if applicable)
• Appropriate CHANGELOG.md files updated for non-trivial, user-facing changes
• Changes in public API reviewed (if applicable)

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: Vaiz / name: Vaiz (01327fa, 71f480d)