Fix GPStore transaction validation semantics

[YWDJ123]

This PR fixes several GPStore transaction validation issues found during cross-validation with TuGraph on SF1-SF100 datasets.

Changes include:

• Fix CR1 traversal state handling and result id handling.
• Fix CR2 reverse transfer traversal semantics.
• Fix CR3 no-path / missing-vertex result consistency.
• Fix CR9 floating point precision issues.
• Fix RW1 cycle detection false positives.
• Fix GPStore data conversion header generation for relation endpoint labels.

Validation:

• Cross-validation passed on SF1, SF10, SF30, and SF100 after applying these fixes.