[FE-82] Graceful session expiry handling

[mftee]

Overview

When a token expires mid-session — plausibly while a user is partway through uploading and annotating a document — the failure must be handled deliberately rather than dropping them somewhere confusing with their work lost.

Tasks

• Detect 401 centrally and attempt a single refresh, queueing concurrent requests until it resolves.
• Prevent refresh stampedes: many simultaneous 401s must trigger exactly one refresh call.
• On refresh failure, clear session state and redirect to login preserving both the intended destination and the active locale.
• Warn before expiry with a "Stay signed in" prompt rather than dropping the session silently.
• Preserve in-progress form and upload state across the redirect where practical.
• Synchronize logout across tabs via a storage event.
• Add a test proving ten concurrent 401s produce one refresh.

Acceptance Criteria

• An expired token refreshes transparently with no visible failure.
• Failed refresh returns the user to their original page and locale after re-authenticating.
• Concurrent 401s produce exactly one refresh request.

Dependencies

Interacts with the API client work already filed.

Notes for Contributors

Comment below to be assigned.

[martoniel]

@martoniel has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Good day Big Dev! Pls I would love to work on this issue carefully and make PR today

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[Heazzy500]

@Heazzy500 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

my applications

Hello Maintainer, I’ve reviewed the issue description and I’m confident I can work on it effectively. Please assign it to me.

Hi! I’d love to contribute to this issue. It looks interesting and I’d be happy to take it on if it’s still available.

Hello, I’ve gone through the requirements and I’m confident I can implement a proper solution that matches the acceptance criteria. Kindly assign this issue to me.

Hi Maintainer, I’d like to work on this issue. I have experience handling similar tasks and can start immediately.

Hello, I’m interested in working on this issue and would appreciate being assigned to it. Thank you.

Hi there, I carefully reviewed the issue details and I’m confident I can deliver a clean and efficient solution.

Hello Maintainer, I’d love to take ownership of this issue and submit a high-quality pull request once completed.

Hi, I’m a full-stack Web2 & Web3 developer with open-source contribution experience, and I’d be glad to work on this issue.

Hello, this issue aligns well with my skill set and I’m confident I can resolve it properly. Please assign it to me.

Hi Maintainer! I’m interested in contributing to this task and can ensure timely delivery with clean implementation.

Hello, I’ve thoroughly read the issue description and understand the expected outcome. I’d love to work on it.

Want me to clean these up into one stronger template you can reuse?

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[oladev2026-tech]

@oladev2026-tech has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Hi can i work on this task? Kindly assign

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[drips-wave]

Congratulations, @oladev2026-tech! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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