fix: increase polling grace period to prevent false transfer errors (FCT2-20905)

[HasanCPS]

PR checklist

Correctness

• Does what the ticket asks for

Keeping it simple

• Doesn't rebuild something that already exists in the codebase
• No more complex or slower than it needs to be
• No leftover debug logging or commented-out code

Easy to miss (a green pipeline won't flag these)

• One logical change, not a pile of unrelated stuff

When a transfer is initiated, the API returns 202 Accepted immediately but the Durable Entity that tracks transfer status is only created once the orchestrator starts running. On cold starts, the orchestrator can take longer than 30 seconds to spin up.

The UI polls for transfer status and previously had a 30-second grace window for 404 responses before surfacing an error. This caused users to see "Transfer not found" errors even though the transfer completed successfully in the background.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues
0 New dependency risks

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

See analysis details on SonarQube Cloud