Route JPAInsertClause.execute() through native SQL when values contain function templates (#1757)

[zio0911]

Summary

JPAInsertClause.execute() and HibernateInsertClause.execute() now route through JpaNativeInsertSerializer (native SQL) when value expressions contain a TemplateExpression — typically a schema-qualified function call from SQLExpressions.function/stringFunction/numberFunction or a raw SQL fragment. Plain path/literal/parameter INSERTs continue to use the existing JPQLSerializer path so JPA semantics (cascade behaviour for paths, callbacks where applicable) are preserved.

Aligns execute() with the native routing that executeWithKey() / executeWithKeys() (#1693) already use, so callers no longer need to invoke a key-returning method purely to dodge the JPQL parser when their values contain function templates.

Fixes #1757.

Changes

• JPAInsertClause.execute() — detect template values via a new hasTemplateValue() helper and dispatch to native path when present, falling back to JPQL otherwise.
• HibernateInsertClause.execute() — same change applied with Session.doReturningWork(...) instead of EntityManager.unwrap.
• JpaInsertNativeHelper — added executeUpdate(Connection, String, Object[]) for the non-key-returning native path. Class javadoc generalized.
• Regression tests in JPAExecuteWithKeyTest and HibernateExecuteWithKeyTest:
  • execute_with_function_template_routes_through_native_sql — verifies that upper({0}) inside a value expression is preserved and the function is evaluated by the DB.
  • execute_without_template_uses_jpql_path — verifies plain INSERTs still go through JPQL.

Test plan

• ./mvnw -Pdev -pl querydsl-libraries/querydsl-jpa -am test — 3238 tests, 0 failures
• JPAExecuteWithKeyTest (13 tests, includes 2 new execute_* cases)
• HibernateExecuteWithKeyTest (includes 2 new execute_* cases)
• Verified end-to-end in a downstream Spring/JPA consumer doing INSERT with a schema-qualified external SQL function — pre-patch reproduced the SemanticException from JPAInsertClause.execute() does not route to native SQL when values contain function templates / SQL fragments #1757; post-patch the INSERT succeeds via the native path.