PR summary

Add a fast path for np.delete when given an empty integer indexer. The result is still a copy, matching the existing delete contract, but avoids allocating and applying a full boolean keep mask.

ASV quick comparison against main:

bench_function_base.Delete.time_empty_indices((100, 100), None): 29.0 us -> 24.6 us
bench_function_base.Delete.time_empty_indices((100, 100), 0):    34.6 us -> 28.5 us
bench_function_base.Delete.time_empty_indices((1000,), 0):       29.8 us -> 20.5 us
bench_function_base.Delete.time_empty_indices((1000,), None):    45.0 us -> 31.3 us

First time committer introduction

I am a NumPy user/contributor looking at small, focused performance improvements in common array operations. I will handle review discussion and follow-up changes directly.

AI Disclosure

LLM / Harness: hybrid.

AI assistance was used to inspect the codebase, run local commands and benchmarks, draft PR text, and help prepare candidate patches. I reviewed the generated suggestions, selected the final changes, and am responsible for the code, submission, and follow-up discussion. Some PR text and candidate code edits were drafted with AI assistance; the final patch and text were reviewed and edited by me.