Function validate_schema 

pub async fn validate_schema<M: HasSchema>(db: &Db) -> SchemaReport

Validate the schema of a single model against the live DB.

The model’s T::SCHEMA (from the HasSchema trait — typically generated by #[derive(RustioModel)]) is the expectation. The DB is the source of truth at runtime; any drift is recorded in the returned SchemaReport.

Read-only — issues two SELECT statements against information_schema and exits.