od: wrap offset instead of overflowing on a large --traditional label

[AlejandroCoronadoN]

Summary

In --traditional mode, od accepts a pseudo-address label. A label near u64::MAX
overflows the offset accumulator on the first read:

$ printf '0123456789ABCDEF' | od --traditional - 0 0xffffffffffffffff
thread 'main' panicked at src/uu/od/src/input_offset.rs: attempt to add with overflow
$ echo $?
101

(under -C overflow-checks).

Root cause

InputOffset::increase_position used unchecked u64 arithmetic
(self.byte_pos += n, self.label = Some(l + n)).

Fix

Use wrapping_add. The byte offset and label are fixed-width addresses, so wrapping
(as GNU od does) is the correct behavior and cannot overflow. Adds a unit test.

Fixes #13225.

[codspeed-hq]

Merging this PR will degrade performance by 18.61%

⚠️ Different runtime environments detected

Some benchmarks with significant performance changes were compared across different runtime environments,
which may affect the accuracy of the results.

Open the report in CodSpeed to investigate

❌ 1 regressed benchmark
✅ 346 untouched benchmarks
⏩ 46 skipped benchmarks¹

Warning

Please fix the performance issues or acknowledge them on CodSpeed.

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
❌	Simulation	df_with_path	573.7 µs	704.9 µs	-18.61%

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 AlejandroCoronadoN:fix-od-traditional-offset-overflow (573a3a8) with main (822aa83)}

Footnotes

1. 46 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. ↩