Preserve WITH clauses when deparsing VALUES statements

[minleejae]

StatementDeParser drops the CTE from a top-level WITH ... VALUES query. For example, WITH cte(foo) AS (VALUES (42)) VALUES ((SELECT foo FROM cte)) currently renders as VALUES ((SELECT foo FROM cte)), leaving an undefined relation. The original query was executed successfully on PostgreSQL 18.6 during corpus validation.

Reuse the existing WITH-item deparser support for VALUES, preserving the configured select/expression visitors and their context. Keep the existing constructor and add a select-deparser/context path for callers. When VALUES is nested in an expression, let its deparser own the WITH clause so it is emitted exactly once.

Tests cover direct and statement deparsing, multiple/recursive/materialized CTEs, a data-modifying CTE, nested VALUES queries, custom visitor rewriting, callback context, and an unchanged source AST. No grammar changes are required.

Validation: all production sources compiled with Java 17, and all 32 tests passed across ValuesWithDeParserTest, ValuesTest, and DmlSourceExpressionTest using the offline JUnit runner. Manual round trips for the original/nested query forms also passed. Full Gradle/Maven checks remain for CI. Executing the patched output against PostgreSQL has not been repeated because local DB access is blocked.