Make Passkey Registration Atomic With Credential-ID Persistence

[maugauwi-hash]

Labels: bug, ios, passkey
Priority: Medium
Estimated Time: 1 hour

Description:
AuthStore.register() calls PasskeyService.shared.register(username:), which itself already
calls APIClient.shared.registerPasskey(...) — i.e., the backend registration completes — and
only afterward does AuthStore call KeychainService.shared.saveCredentialID(credID). If the app
is killed between those two lines, the backend has a registered passkey but the device has no
local record of the credential ID, silently breaking ICloudSyncService associations later.

Tasks:

• Move saveCredentialID into PasskeyService.register() itself, immediately after the backend call succeeds
• Add a crash-safety test (simulate termination between backend success and local persistence)
• Document the invariant that credential ID persistence must never trail the backend call

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[maztah1]

@maztah1 has applied to work on this issue as part of the Stellar Wave Program's 7th wave.

Can i solve this issue please

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[drips-wave]

Congratulations, @maztah1! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on July 30, 2026.

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