[illuminati1911]

Summary

Add Client.addressvalidation_feedback(response_id, conclusion) for Google’s Address Validation feedback operation.

• Submit the first validation response ID and a supported conclusion.
• Reject invalid inputs before transport and return {} on success, including empty HTTP bodies.
• Reuse existing Address Validation error handling and transient retries without changing validation behavior.
• Add regression coverage, public method documentation, and an Unreleased changelog entry.

Dependency

Stacked on #6, targeting address-validation-errors so the diff contains only feedback support.

Evidence

• Google REST contract
• Implementation

Verification

• Address Validation module: 12 tests passed.
• Full suite: 116 tests passed; statement coverage is 88.75%, with no decrease from the parent.
• Repository documentation built without warnings using the Python 3.10 fallback; Python 3.7 was unavailable.
• Real localhost HTTP smoke passed for validation, feedback, errors, and retries.
• Live validation returned HTTP 403 PERMISSION_DENIED; no live feedback request was sent.