[RaphaelFakhri]

Fixes #577

Summary

logger.error('save failed', { error }) logged "error":{}. name, message, stack and cause are non-enumerable on Error, so JSON.stringify drops them.

format() in packages/void/src/runtime/log.ts now passes a replacer to JSON.stringify. The replacer writes each Error as its own enumerable fields plus name, message, stack and cause. This covers nested errors and cause chains. The { msg, ...fields } shape is unchanged. An error that appears a second time (for example error.cause = error) is written as { name, message }, so serialization terminates and the other fields are kept.

An error with its own toJSON still uses it, because JSON.stringify calls toJSON before the replacer.

Tests

New cases in packages/void/test/unit/runtime-log.test.ts:

• Error fields keep name, message, stack and cause.
• Error subclasses keep their own enumerable fields (status).
• A cyclic cause does not drop the other fields.

vp test run packages/void/test/unit/runtime-log.test.ts: 3 failed, 12 passed without the fix; 15 passed with it. vp lint and vp fmt --check are clean on the changed files.

Docs

docs/reference/api/resources.md notes that you can pass a caught Error in fields.