Add scan execution counters

[palaska]

Summary

Scan counters now distinguish split statistics rejection, predicate rejection, and whole-file statistics skips.

Changes

• New APIs expose fresh counters for each execution and define cancellation behavior.
• Registry totals update after each execution stops. Conjuncts and dynamic updates do not duplicate counts.
• Dynamic file checks use cached results. Disabled scans omit counter updates.
• Row-index rejection counts as predicate rejection.

Validation: All 15 scan counter tests passed on the final commit. No performance benchmarks ran.

[codspeed]

Merging this PR will degrade performance by 13.59%

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

⚠️ 1 benchmark measured no execution time

Nothing ran under measurement, usually because the compiler removed the code under test. This result is not comparable, so it counts as unchanged.

Preventing compiler optimizations

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

⚡ 1 improved benchmark
❌ 2 regressed benchmarks
✅ 2172 untouched benchmarks
⏩ 434 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	density_sweep_dense_runs[0.001]	29.5 µs	47.6 µs	-37.94%
❌	WallTime	bitpack_blocked_compress_avx2	6.7 µs	7.6 µs	-12.2%
⚡	WallTime	bitpack_blocked_compress_avx512	5.7 µs	4.8 µs	+18.42%
⚠️	Simulation	bench_compare_primitive[(10000, 2)]	< 1 ns	< 1 ns	N/A

Tip

Investigate this regression by commenting @codspeedbot fix this regression on this PR, or directly use the CodSpeed MCP with your agent.

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_{Comparing bp/scan-execution-counters (eddb40c) with develop (3414802)}

Footnotes

1. 434 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩