feat(payments): add optional amount to VoidRequest for partial voids

[armando-rodriguez-cko]

Summary
Adds the optional amount field to the payment void request, introduced in the API spec on 2026-08-13. When set, only that amount is voided; when omitted, the full payment amount is voided, exactly as before.

Changes

• Void request model: new optional amount (integer, min 0, max 9999999999) with doc comment
• Serialization tests: amount present when set, and absent from the body when unset, so existing full-void callers keep sending an identical payload

API Reference

• POST /payments/{id}/voids (VoidRequest.amount)

Breaking changes
None.

README
No README impact.

[agent-wall-e]

🟢 Risk Classification: LOW

Approval route: AI Auto-Approval
Rollback controls: Automated Instant Rollback + feature flags

Classification reasons

• no_low_class_matched
• prod_source_modified
• 2.2.6_logical_extension:Adds a single optional field to an existing request model with no new endpoints, persisted data, auth changes, or external integrations, and existing callers are unaffected when the field is omitted.

Operational gates

• ✅ jira_ticket (INT-1689)
• ✅ independent_review

Files analysed: 2

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[agent-wall-e]

🔬 Debug — why this classification?

Each reason code emitted by the classifier, its source clause in the AI in SDLC Control Framework, and what it means.

Reason code	Kind	Clause	Meaning
no_low_class_matched	informational	§2.2 (fall-through)	None of the deterministic Low classes (§2.2.3, §2.2.4, §2.2.7, docs-only) applied; classifier fell through to LLM evaluation.
prod_source_modified	informational	§2.1 M7 (informational)	At least one file is non-doc, non-test, non-IaC — i.e. application source code was modified.
2.2.6_logical_extension — Adds a single optional field to an existing request model with no new endpoints, persisted data, auth changes, or external integrations, and existing callers are unaffected when the field is omitted.	classifying	§2.2.6	Sonnet 4.6 evaluator promoted minor → low: the change reuses existing code paths and does not cross a trust boundary.

Kinds:

• classifying — this rule contributed to the chosen tier.
• informational — context only; did not by itself decide the tier.

See issue #3 for the proposal to formalise this map as Appendix A of the standards doc.

_{wall-e 2026.06.19-02 · debug}

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[agent-wall-e]

✅ Auto-approved — this PR meets all Low-risk criteria.

All checks passed, no unresolved comments, and the change classification is:

• no_low_class_matched
• prod_source_modified
• 2.2.6_logical_extension:Adds a single optional field to an existing request model with no new endpoints, persistence, auth changes, or external integrations, and existing callers are unaffected when the field is omitted.

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