test(compliance): AlreadyInitialized error on double initialize

[Phantomcall]

PR: test(compliance): AlreadyInitialized error on double initialize

Summary

Adds an explicit test verifying that calling initialize twice on the same ComplianceContract instance returns ContractError::AlreadyInitialized.

Context

The initialize function in contracts/compliance/src/lib.rs:22-30 already guards against double initialization by checking if the Admin storage key exists and returning Err(ContractError::AlreadyInitialized) if set. This guard is critical for security — without it, an attacker could re-initialize the contract and seize admin control.

An explicit regression test ensures this guard is not accidentally removed or broken during future refactoring.

Test added

reinitialize_is_rejected in contracts/compliance/tests/compliance_test.rs:239-244

• Calls setup() which invokes initialize once with a legitimate admin.
• Attempts a second initialize call via try_initialize with a different address.
• Asserts the result is Err(Ok(ContractError::AlreadyInitialized)).

Verification

The test passes under cargo test --package compliance (Soroban environment).

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Closes #77