cp: Fix panic when recursively copying a directory with a non-UTF8 name #11148

Performance Gate Passed

⚡ 2 improved benchmarks
✅ 292 untouched benchmarks
⏩ 42 skipped benchmarks¹

	Mode	Benchmark	`BASE`	`HEAD`	Efficiency
⚡	Simulation	`shuf_input_range[1000000]`	89.7 ms	84.2 ms	+6.49%
⚡	Simulation	`cp_large_file[16]`	391.3 µs	379 µs	+3.25%

_{Comparing Zellic:cp-fix-nonutf8-panic (40d7ba7) with main (a611f98)}

42 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. ↩