[OskarEichler]

Summary:

• return an Enumerator when Proxy::Errors#each is called without a block
• iterate values directly without allocating an intermediate key/value array
• report delegated Hash methods through respond_to_missing?

Reproduction:

On current main, errors.each raises LocalJumpError, despite including Enumerable, and errors.respond_to?(:keys) is false even though errors.keys works through method_missing.

Verification:

• bundle exec rake spec — 224 examples, 0 failures on Ruby 4.0.6 / Rack 3
• focused enumeration/introspection model passes on current main and the cumulative v1.2.9 consumer
• Ruby syntax and git diff --check pass

Existing block iteration continues yielding each non-empty message array. Codex assisted with the audit and patch.