starknet_transaction_prover: add prover input validation unit tests

[avi-starkware]

Adds unit tests for VirtualSnosProver input validation: pending block
rejection, DeployAccount rejection, proof/proof_facts field rejection,
non-zero fee field rejection (with the validation knob respected when
disabled), and a happy-path test that asserts a valid invoke reaches
the runner.

Adds two test runners — UnreachableRunner (panics on invocation, for
tests where validation must reject the input) and FailingRunner (returns
an error, for tests that must verify the runner is reached without
needing a real node).

[reviewable-StarkWare]

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[avi-starkware]

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• starknet_transaction_prover: add deployment smoke script and guide #14052
• starknet_transaction_prover: add manual testing guide #14404
• starknet_transaction_prover: make RPC error spec test exhaustive via enum #14051
• starknet_transaction_prover: add TLS integration tests #14050
• starknet_transaction_prover: add ServiceConfig validation tests #14049
• starknet_transaction_prover: add CORS validation unit tests #14048
• starknet_transaction_prover: add prover input validation unit tests #14047 👈 (View in Graphite)
• starknet_transaction_prover: add committer utils unit tests #14046
• starknet_transaction_prover: add request body size limit tests #14403
• main-v0.14.3

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PR Summary

Low Risk
Test-only and pub(crate) constructor refactors; production ProverConfig behavior is unchanged.

Overview
Adds unit tests for VirtualSnosProver::prove_transaction input validation without a real RPC node, using mock VirtualSnosRunner implementations.

Prover test hooks: from_runner / from_runner_with_blocking_check now delegate to a shared from_runner_with_options that sets validate_zero_fee_fields. A new from_runner_without_fee_validation lets tests send non-zero fee fields and still reach the runner when exercising other gates.

Test doubles: UnreachableRunner panics if invoked (assert validation rejected early); FailingRunner returns a fixed RunnerError so tests can prove the runner was reached.

Coverage: Rejects pending blocks, DeployAccount, non-empty proof / proof_facts, and non-zero fee fields when validation is on; with validation off, non-zero resource bounds pass through to the runner; a valid invoke is shown to hit the runner. Also adds an ignored Sepolia balanceOf integration test and small shared helpers (valid_invoke, dummy_account).

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