Function is_missing_column_or_table 

fn is_missing_column_or_table(e: &Error) -> bool

True iff the error is SQLite reporting “this column/table doesn’t exist in this DB’s schema.” Distinguishes a pre-v8 DB (skip silently — those agents weren’t named, so wouldn’t appear in the dropdown anyway) from corruption (caller logs + continues + defers the marker).

rusqlite reports prepare-time schema mismatches as Error::SqlInputError { msg, sql, offset } and runtime errors as Error::SqliteFailure(_, Some(msg)). Both shapes carry the canonical SQLite phrases, but only message inspection distinguishes them from other failures with the same error code.