Clone structuredClone error causes deeply

[OskarEichler]

Summary:

The structured-clone polyfill copies Error.cause by reference and only when truthy. Recursively clone every own cause value after registering the cloned Error in cycle memory, preserving object/circular identity, falsy causes, and the standard non-enumerable descriptor.

Fixes #58206.

Changelog:

[GENERAL] [FIXED] - Deeply clone Error causes, including circular and falsy values.

Test Plan:

• Exact baseline reproduced three failures: object cause remained shared, circular cause pointed to the input, and false became undefined.
• Fixed focused Fantom suite: 33/33 passed; result values and circular identity match Node's native structuredClone.
• Fresh yarn flow-check: 0 errors.
• Targeted ESLint, Prettier, and git diff --check passed.

No UI change; screenshots are not applicable.