feat(compute): add cumulative_sum and cumulative_sum_checked

[fallintoplace]

Rationale for this change

Arrow-Go has array and chunked-array compute kernels, but no cumulative sum operation for running totals. Adding this as a vector kernel also gives chunked inputs the same stateful behavior as a single contiguous array.

What changes are included in this PR?

• Add cumulative_sum for signed integers, unsigned integers, and floating-point arrays.
• Add cumulative_sum_checked, which reports integer overflow instead of returning an overflowing result.
• Add CumulativeOptions with a start value and SkipNulls. By default, a null stops the cumulative result; with SkipNulls, null positions remain null while later valid values continue from the previous sum.
• Validate cross-type start values with the same safe numeric conversion rules used by compute casts.
• Carry the running state across chunks and keep the output chunked.

Are these changes tested?

• go test ./arrow/compute/... -count=1
• Added coverage for normal sums, null propagation, skipped nulls, start values, rejected overflow and truncation in start values, chunked input, and checked overflow at every integer width.

Are there any user-facing changes?

Yes. This adds the public compute.CumulativeSum and compute.CumulativeSumChecked functions plus CumulativeOptions. Existing functions and APIs are unchanged.