Validates a PostgreSQL schema name and returns it double-quoted for safe
interpolation into DDL (schema names cannot be passed as bind parameters).
Only simple identifiers are allowed (letter/underscore start, then
letters/digits/underscores/$, max 63 bytes), which both keeps the value
injection-safe and avoids surprising case-folding / quoting edge cases.
Validates a PostgreSQL schema name and returns it double-quoted for safe interpolation into DDL (schema names cannot be passed as bind parameters).
Only simple identifiers are allowed (letter/underscore start, then letters/digits/underscores/
$, max 63 bytes), which both keeps the value injection-safe and avoids surprising case-folding / quoting edge cases.