Function schema_in_supported_range 

pub fn schema_in_supported_range(v: u32) -> bool

Pure boundary check: true when v lies within [MIN_SUPPORTED_SCHEMA, MAX_SUPPORTED_SCHEMA]. Extracted so the boundary semantics (inclusive both ends) can be unit-tested without needing a synthetic DB whose schema_version lies outside the migration ladder’s reach. v0.6.3.1 (PR-9h / issue #487 PR #497 req #72).