Cover the Verified attestation path cross-contract, reusing the real tee-verifier

[pbeza]

Background

#3714 moved DCAP verification into the tee-verifier contract, called from submit_participant_info via a cross-contract Promise. The sandbox tests from #3715 drive the real deployed verifier, but only for the failure verdicts; the Verified verdict and the store path are covered in-process only, because the fixture collateral is time-expired against the forward-only sandbox clock. A stub verifier was deliberately dropped in #3715, so the coverage must reuse the real contracts.

User Story

As an MPC contract maintainer, I need the Verified attestation path exercised against the real deployed verifier, so that wire-format, gas-budget, and storage regressions are caught in CI instead of on a live TDX deployment.

Acceptance Criteria

• A sandbox test drives submit_participant_info through the real tee-verifier WASM to a Verified verdict at the production verifier_tera_gas budget.
• No stub or duplicated test-only verifier contract; a cfg-gated test hook in the real crate is acceptable.
• Store-path tests that must sign as the fixture account land guarded until the fixture secret key asset exists (test(contract): exercise the Verified attestation store end-to-end in sandbox (fixture account key + measurements helper) #3787).
• E2E clusters deploy and vote in the tee-verifier for topology parity with production.

Resources & Additional Notes

Related: #3714, #3715, #3738, #3787, #3897. Testing section of docs/design/attestation-verifier-contract.md.