Add TPC-H test suite

**Is your feature request related to a problem? Please describe.**
Auron currently lacks sufficient end-to-end (E2E) test coverage, which makes it more difficult to detect execution plan changes introduced by code updates and to catch correctness issues in query results.

**Describe the solution you'd like**
Introduce a lightweight TPC-H dataset and add an E2E TPC-H test suite:
+ Validate results for the standard TPC-H queries
+ Verify query plans/operators to ensure expected execution strategies
+ Make the suite easy to run locally and in CI

**Describe alternatives you've considered**

**Additional context**