Mock Soroban score-registry for local integration tests

[Cbiux]

Summary

Build a mock Soroban score-registry contract for local integration tests so gatekeeper (#28) and server attestation flows can be tested without testnet deploy (#16).

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Background

Contract tests exist in Rust #[test], but Server soroban.service.ts and future gatekeeper consumers need a deployable mock returning configurable scores for CI.

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Deliverables

Directory: Contracts/mock-score-registry/

Function	Behavior
init()	No admin auth required in mock
set_mock_score(wallet, score, tier)	Anyone can set (test only)
get_score(wallet)	Returns configured mock
interface_version()	Returns 1

Server test helper:

// Server/src/test-helpers/mock-soroban.ts
export function withMockContractId(id: string): void

CI: Optional stellar contract build job for mock contract

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Acceptance criteria

• Mock contract builds with stellar contract build
• README with local deploy instructions
• Server integration test reads mock score via RPC (testnet or local sandbox)
• Clearly marked TEST ONLY — never deploy to mainnet
• Referenced from Contracts/interfaces/README.md

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Related

• Deploy score-registry Soroban contract to Stellar testnet #16 testnet deployment
• [SC] Score Gatekeeper PoC: enforce min tier in lending txs #28 Score Gatekeeper PoC
• [SC] Standard IZCoreScore interface for partner integrations #32 IZCoreScore interface

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Out of scope

• Production registry migration
• WASM size optimization

[snkk2x-collab]

/attempt #64

[Cbiux]

Resuelto en b10ae0b: Contracts/mock-score-registry, test helper withMockContractId, cargo test en CI.