[Emeka-Gerald]

Summary

Adds comprehensive Soroban contract interface compatibility coverage and hardens the checker against malformed or untrusted RPC metadata.

Tasks

• Validate return types, events, errors, duplicate methods, and malformed parameters
• Add unit coverage for success, boundary, invalid-input, failure, and secret-redaction cases
• Add integration coverage for RPC resolution, per-network caching, retries, and fail-closed behavior
• Add the missing metadata cache used by the resolver and restore public exports
• Document configuration, failure semantics, resource/upgrade impact, telemetry, and escalation

Verification

• tests/soroban/compatibility/soroban-contract-compatibility-checker.spec.ts — 31 passed
• test/integration/stellar/soroban-contract-interface-compatibility.spec.ts — 4 passed
• tests/contracts/metadata/soroban-metadata-resolver.spec.ts — 28 passed
• Related compatibility suites — 51 passed
• tsc --noEmit and Prettier checks pass

Closes #1335
closes #1336
closes #1337
closes #1338