Documentation_validate_milestone_wrong_status.md

Test: validate_milestone rejects non-Active vaults

Purpose

• Ensure validate_milestone cannot be used once a vault leaves Active.
• Prevent invalid state transitions and repeated milestone validation.

Covered statuses

• Completed
• Failed
• Cancelled

Security impact

• Enforces lifecycle integrity: only Active vaults can be validated.
• Reduces risk of double-processing milestone outcomes after completion, failure, or cancellation.

Verification

• Added test: test_validate_milestone_rejects_non_active_statuses
• Expected error for each case: Error::VaultNotActive