fix: validate buffer slice alignment

[0ax1]

Prevent slices from reporting an alignment stronger than their source buffer and cover preferred-versus-required alignment propagation.

[codspeed-hq]

Merging this PR will degrade performance by 7.98%

⚠️ 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.

⚡ 2 improved benchmarks
❌ 4 regressed benchmarks
✅ 2124 untouched benchmarks
⏩ 106 skipped benchmarks¹
🗄️ 4 archived benchmarks run²

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	WallTime	arrow_checked_add_u32_neon[16384]	13.5 µs	20.3 µs	-33.68%
❌	WallTime	multiply_shapes_neon[(128, ConstantPerRow)]	3.1 µs	3.8 µs	-16.67%
❌	WallTime	add_shapes_neon[(128, PerRowConstant)]	3 µs	3.5 µs	-15.18%
❌	WallTime	subtract_shapes_neon[(128, PerRowNullableConstant)]	3.7 µs	4.1 µs	-10.71%
⚡	WallTime	arrow_checked_add_u32_avx2[16384]	21.3 µs	17.7 µs	+20.46%
⚡	WallTime	arrow_checked_add_u32_avx512[16384]	21.2 µs	17.6 µs	+20.43%

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 ad/validate-buffer-slice-alignment (66a433a) with develop (59a056d)}

Footnotes

1. 106 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. ↩

2. 4 benchmarks were run, but are now archived. If they were deleted in another branch, consider rebasing to remove them from the report. Instead if they were added back, click here to restore them. ↩

[robert3005]

one of the tests you added here is still failing