Add ForEachErr() func

[mai7star]

Description:
This PR introduces ForEachErr, a utility function that iterates over a collection and invokes a provided callback for each item. If the callback returns a non-nil error, ForEachErr stops processing and returns that error immediately. This makes it easier to perform per-item operations that may fail and to propagate errors without manual loop boilerplate.

Why:

• Reduces repetitive boilerplate for error-aware iteration.
• Provides a clear and consistent pattern for early-exit item processing.

What changed:

• Adds the ForEachErr implementation.
• Adds accompanying unit tests and/or examples demonstrating typical usage.
• No changes to existing public APIs or behavior beyond adding this new helper.