Function validate_allocations 

pub fn validate_allocations<P: AllocationPolicy>(
    ledger: &AllocationLedger,
    snapshot: DeclarationSnapshot,
    policy: &P,
) -> Result<ValidatedAllocations, AllocationValidationError<P::Error>>

Validate a committed ledger and current declarations before opening.

This is the authority boundary for ValidatedAllocations: the historical ledger must pass compatibility and committed-integrity checks before current declarations are checked against framework policy and ledger history. This proves allocation ABI safety only. It does not prove store-level schema compatibility.