Drop the fallible dtype lookup from stats rewrites

[robert3005]

What

The tracked work item asked to replace a recursive tree-walking validation in the stats
rewrite with the dtype stored on each BoundExpression node. That walk is already gone:
#9192 replaced expr.return_dtype(scope) with the field lookup, and it is on develop.

What survived is the wrapper around it. StatsRewriteCtx::return_dtype dates from when the
context held a scope and the lookup walked the subtree. Today it clones the dtype and wraps
an infallible field read in a VortexResult, which hides from rule authors that reading a
type is free.

This removes it. Call sites read BoundExpression::dtype directly.

With the last fallible dtype lookup gone, two helpers simplify:

• geometry_and_constant no longer needs the rewrite context or the VortexResult wrapper,
  so it returns a plain Option.
• non_nan_check no longer needs the context at all.

Guarantees

Acceptance and rejection of predicates are unchanged:

• ensure_predicate matches DType::Bool(_) on the same value it did before.
• The .ok()? in stat_expr guarded an error the lookup could not produce.

Checks

• cargo nextest run -p vortex-array -p vortex-spatial -p vortex-layout -p vortex-file —
  4041 passed, 1 skipped
• cargo test --doc -p vortex-array — pass
• cargo clippy --all-targets --all-features — clean
• cargo +nightly fmt --all

🤖 Generated with Claude Code

[codspeed-hq]

Merging this PR will degrade performance by 10.78%

⚠️ 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.

❌ 3 regressed benchmarks
✅ 2127 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
❌	Simulation	compact[(1024, 90)]	1.3 µs	1.5 µs	-11.14%
❌	Simulation	compact[(2048, 90)]	1.4 µs	1.5 µs	-10.72%
❌	WallTime	mul_u32_nonnull_avx512	5.6 µs	6.2 µs	-10.48%

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 perf/skip-recursive-predicate-revalidation (84c71a5) 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]

Closing: keeping changes local per robert