[claude] Add SafeDiv binary operator

[connortsui20]

Summary

Adds Operator::SafeDiv — a division variant where a non-null zero
divisor yields 0 rather than erroring. Integer overflow still errors
(i32::MIN / -1), matching Div. Null on either side propagates.

Implementation

The array-level kernel is a hand-written single-pass
match_each_native_ptype! loop (not a composition of existing ops). It
runs over primitive slices once, combining validity from both inputs
and producing a PrimitiveArray directly.

Wiring touches the usual places a new binary arithmetic operator hits:
proto enum and generated bindings, Operator / NumericOperator with
their conversions, the Binary scalar-fn dispatcher (including
stat_falsification), scalar-level checked_binary_numeric for both
primitive and decimal scalars, and the FFI C enum.

To combine validity from the two input arrays, the kernel calls
Validity::and and then eagerly materializes the resulting lazy
Binary(And) expression via execute::<BoolArray>(ctx). This required
threading ExecutionCtx through execute_numeric from the Binary
dispatcher.

Scope note: array-level SafeDiv is primitive-only. A decimal-array
input fails with a clear error rather than silently inheriting the
zero-rhs-errs behavior from arrow-arith; scalar-level decimal SafeDiv
(used by the constant-constant fast path) is supported.

Testing

• 5 primitive scalar tests (integer, integer-by-zero, overflow still
  errs, float-by-zero yields 0.0 not Inf, null propagation)
• 1 decimal scalar test (by-zero yields zero, not None)
• 4 array-level tests (integer-by-zero, float-by-zero, nullable
  propagation from both sides, constant-zero rhs fast path)
• Conformance harness: SafeDiv added to the operator arrays and is
  exercised with zero-valued scalars (unlike Div, which is skipped)
• cargo test -p vortex-array --lib → 2556 passed, 0 failed
• cargo clippy -p vortex-array -p vortex-ffi -p vortex-proto --all-targets --all-features → clean
• cargo fmt --all → clean (nightly fmt unavailable in this sandbox)

Signed-off-by: Claude noreply@anthropic.com

https://claude.ai/code/session_01MLXfBVfMbrUgRPafnt5GHC
Signed-off-by: Claude noreply@anthropic.com

[codspeed-hq]

Merging this PR will improve performance by 29.38%

⚡ 1 improved benchmark
✅ 1162 untouched benchmarks
⏩ 1457 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	chunked_bool_canonical_into[(1000, 10)]	59.8 µs	46.3 µs	+29.38%

---

_{Comparing claude/add-safe-division-u28Ep (b5224d3) with develop (24fcc56)}

Footnotes

1. 1457 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. ↩