[WALLET-184] Add response_uri to DC API request

[frostevent]

Summary

Adds two fields to the signed DC API request path in packages/server:

• response_uri — added to the DCAPIAuthorizationRequest payload, populated from the client's configured callbackUri.
• expected_origins — a new required expectedOrigins parameter on signedDcApiRequest, typed as a non-empty array ([string, ...string[]]) and validated at runtime (rejects an empty array). It is emitted as expected_origins in the signed request payload.

signedDcApiRequest is now async so the empty-array validation surfaces as a promise rejection, consistent with the other config-validation errors.

Tests

• Existing signedDcApiRequest test updated to pass expectedOrigins and assert response_uri / expected_origins in the signed payload.
• New test covering rejection of an empty expectedOrigins array.
• Full suite passes; yarn check-all (format, lint, build, publint) is green.

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