Add built-in stats rewrite rules

[gatesn]

Summary

• register built-in stats rewrite rules through the session-backed registry
• port comparison, boolean, between, like, list_contains, and cast-aware stat rewrites to StatFn::new_expr(...)
• add aggregate-backed null rewrite rules using all_null and all_non_null
• keep the existing legacy null_count / row_count() rewrite rules so current stored stats continue to work

Tests

• cargo +nightly fmt --all
• cargo test -p vortex-array stats::rewrite::builtins::tests::rewrites_null
• cargo test -p vortex-array stats::rewrite
• cargo clippy --all-targets --all-features

[codspeed]

Merging this PR will improve performance by 19.86%

⚠️ Unknown Walltime execution environment detected

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⚡ 1 improved benchmark
✅ 1236 untouched benchmarks

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	chunked_varbinview_opt_canonical_into[(1000, 10)]	225.1 µs	187.8 µs	+19.86%

Tip

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_{Comparing ngates/stats-7707/built-in-rewrite-rules (cf1c23b) with develop (a8fb30e)}