feat(query): add Query, MustQuery, and UpdateOne helpers

Adds scan-into-dest query helpers and update-one-row semantics with
Context variants, tests, and documentation updates.

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

query.go

@@ -70,3 +70,31 @@ func MustFetchOneContext[T any](ctx context.Context, sqlo Queryable, stmt Statem
 	}
 	return result[0], nil
 }
+
+// Query executes a Jet statement and scans the result into dest.
+func Query(sqlo Queryable, stmt Statement, dest any) error {
+	return QueryContext(context.Background(), sqlo, stmt, dest)
+}
+
+// QueryContext is the context-aware variant of [Query].
+func QueryContext(ctx context.Context, sqlo Queryable, stmt Statement, dest any) error {
+	return stmt.QueryContext(ctx, sqlo, dest)
+}
+
+// MustQuery executes a Jet statement and scans the result into dest. If the
+// query returns no rows, notFoundErr is returned instead of [ErrNoRows].
+func MustQuery(sqlo Queryable, stmt Statement, dest any, notFoundErr error) error {
+	return MustQueryContext(context.Background(), sqlo, stmt, dest, notFoundErr)
+}
+
+// MustQueryContext is the context-aware variant of [MustQuery].
+func MustQueryContext(ctx context.Context, sqlo Queryable, stmt Statement, dest any, notFoundErr error) error {
+	err := stmt.QueryContext(ctx, sqlo, dest)
+	if err != nil {
+		if errors.Is(err, ErrNoRows) {
+			return notFoundErr
+		}
+		return err
+	}
+	return nil
+}