feat(ksuid): add BinExpr, flexible parsers, and expression helpers

Adds ParseStringKSUIDAny, ParseBinaryKSUIDAny, BinaryKSUID.BinExpr, and
ExprStringKSUIDs for portal-compatible KSUID handling at API boundaries.

Co-authored-by: Cursor <cursoragent@cursor.com>

jet_expr.go

@@ -24,3 +24,12 @@ func ExprStringers(values []fmt.Stringer) []Expression {
 	}
 	return expressions
 }
+
+// ExprStringKSUIDs converts StringKSUID pointers to Jet string expressions.
+func ExprStringKSUIDs(ids []*StringKSUID) []Expression {
+	expressions := make([]Expression, len(ids))
+	for i, id := range ids {
+		expressions[i] = mysql.String(id.String())
+	}
+	return expressions
+}