[Quality][Medium] Improve API error, loading, and empty-state contract: regression, accessibility, and compatibility coverage

[1nonlypiece]

Problem

The current API error, loading, and empty-state contract implementation is a production-quality risk area: All major screens need a consistent error envelope, retry policy, loading boundary, and empty-state distinction.

This issue requires meaningful implementation and focused tests. Typo-only, documentation-only, formatting-only, dependency-only, and cosmetic changes do not satisfy the scope.

Objective

establish a durable regression contract for normal, boundary, accessibility, and compatibility behavior for the implementation anchored at src/app; src/components; src/app/api.

Scope

• Establish the feature's explicit state, data, authorization, and failure invariants.
• Add focused unit and integration tests for success, failure, loading, empty, retry, and permission states.
• Verify keyboard, focus, screen-reader, responsive, and reduced-motion behavior where the feature is interactive.
• Document the supported API/component contract and protect existing consumers from accidental breaking changes.
• Keep the change focused on this feature and preserve unrelated public behavior.

Acceptance criteria

• The implementation defines and enforces the relevant invariants for normal and adversarial inputs.
• Add focused unit and integration tests for success, failure, loading, empty, retry, and permission states.
• Verify keyboard, focus, screen-reader, responsive, and reduced-motion behavior where the feature is interactive.
• Document the supported API/component contract and protect existing consumers from accidental breaking changes.
• Automated tests cover success, failure, boundary, retry, and permission behavior applicable to this feature.
• The PR includes validation commands, design tradeoffs, and any remaining limitations.
• The PR references this issue using Refs #<issue-number>.

Priority

Medium — determined by the potential impact on correctness, user funds or data, security, availability, and implementation depth.

Non-goals

• Do not make typo-only, documentation-only, formatting-only, dependency-only, or cosmetic changes.
• Do not remove tests merely to make CI pass.
• Do not introduce secrets, credentials, unsafe network defaults, or unrelated refactors.

Contributor application

Before starting, comment with relevant experience, a concise implementation approach, the main risks or tradeoffs, and an estimate for opening the first draft PR. Wait for maintainer assignment before coding.

Submission requirements

• Use PR title format: [#<issue-number>] <short summary>.
• Address every acceptance criterion in the PR description and implementation.
• Include focused automated tests and validation results.
• Explain any unavoidable limitations or pre-existing CI failures.
• Address maintainer review feedback before requesting final review.

Quality evaluation will consider scope adherence, implementation quality, test depth, security, correctness, review responsiveness, and follow-up stability.

[kingsrichie79-cmyk]

@kingsrichie79-cmyk has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I’d like to take this issue. I’ve reviewed the requirements and would be happy to work on the implementation and provide a tested solution.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @kingsrichie79-cmyk to this issue.

[VeronicDev]

@VeronicDev has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hi, I can fix this pls assign

ℹ️ Repo Maintainers: To accept this application, review their application or assign @VeronicDev to this issue.

[drips-wave]

Congratulations, @Akeem0604! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

🧑‍💻 @Akeem0604: Please resolve the issue such that the repo's maintainers have enough time to review your contribution before the due date. You'll earn Points for completing the issue on-time, which will make you eligible for a share of the Stellar Wave Program's reward pool.

Warning

When opening a PR, please link it to this issue to ensure it gets tracked accurately. Points are awarded when this issue is marked as completed by the maintainer.

🤠 Repo maintainers: Please keep an eye on the contributor's progress and review their work before the due date. You can manage this issue, including adjusting its complexity and points, here.

🌊 Happy Wave 🌊