pr Execute Universal

We are working in the `<REPO_NAME>` repository.

Implement exactly one selected PR from a previously prepared plan.

General rules:
- Deliver a working implementation, not a stub.
- No TODO/FIXME/placeholder branches in the production path.
- Do not break existing behavior outside the explicitly stated scope.
- Implement only this PR and do not absorb scope from later PRs.
- Keep changes minimal and focused within this PR.
- Do not do unrelated refactors outside the task.
- All new outputs must be deterministic when that is relevant to the task.
- All errors and degradations must be explicit, with no silent fallback.
- If you introduce a new contract, format, artifact, schema, protocol, or config:
  - pin a version (`...v1`);
  - add validation;
  - add stability and determinism tests when applicable.
- You must add or update tests:
  - happy path
  - negative cases
  - regression checks
  - compatibility checks, when applicable
  - stability checks, when applicable
- If there is ambiguity inside scope, choose the safer implementation and call out assumptions explicitly in the answer.
- If the context is not sufficient for full completion, still deliver the safest partial implementation within scope and clearly state the remaining limits.

First, briefly:
1. Confirm how you understood the PR goal.
2. List what is in scope.
3. List what is explicitly out of scope.
4. If you see a risk of hidden scope expansion, call it out before implementation.

Then implement the change.

At the end of the answer, include:
1. the list of changed files,
2. what was implemented,
3. which tests should be run,
4. what limitations or tradeoffs remain,
5. whether there were assumptions,
6. whether there is any hidden scope expansion relative to the original PR.

Here is the PR to implement:
<SELECTED_PR>