feat: Add a new endpoint for faster uploads in relay

[sadhansood]

Description

This PR adds a session based upload relay endpoint for lower latency uploads by accepting systematic primary slivers directly from clients. The client upload workflow using upload relay is now using this experimental endpoint is:

1. Clients create a sliver upload session
2. Upload primary slivers in parallel
3. Complete the session once all required systematic primary slivers are present.

The relay now validates uploaded slivers against the provided blob metadata, uploads metadata and primary slivers to storage nodes with immediate intent as they arrive, derives the remaining primary and secondary slivers during completion, and then finishes the normal storage certification flow.

It also adds support for tipped relay sessions by preflighting and reserving the paid tip transaction at session creation, then verifying the reconstructed raw blob digest against the auth package before completing the upload.

Test plan

Added unit coverage for the sliver upload session flow.

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Release notes

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• Storage node:
• Aggregator:
• Publisher:
• CLI:

[github-actions]

Warning: This PR modifies one of the OpenAPI files. Please consider the
following:

• Make sure the API changes are backwards compatible.
• Make sure to follow existing conventions for any added parameters, requests, and
  responses.
• Make sure the generated HTML files do not contain errors.
• This probably requires release notes and maybe changes to the documentation.

cc @jpcsmith @mlegner

[github-actions]

This PR is stale because it has been open 14 days with no activity. It will be closed in 7 days unless you remove the stale label, add the do-not-close label, or comment on it.

[imamnugrh-web]

commits

[github-actions]

This PR is stale because it has been open 14 days with no activity. It will be closed in 7 days unless you remove the stale label, add the do-not-close label, or comment on it.