Native Histogram Fuzz Failures

[harry671003]

This issue tracks the ongoing efforts to stabilize native histogram support in the Thanos PromQL engine.

Problem

We are currently seeing inconsistent behavior and test failures when native histograms are enabled during fuzz testing. These failures are affecting the overall stability and reliability of the engine in edge cases.

Goal

To reach a state where native histograms pass all fuzz and correctness tests reliably, allowing us to enable them by default without regressions.

[harry671003]

#598 - Implement timestamp() for native histograms

[harry671003]

#596 - Fix output series ID for native histogram binary operations

[harry671003]

#595 - Fix sort() for native histograms

[harry671003]

prometheus/prometheus#16744 - Prometheus bug in last_over_time()