feat(langchain_v1): anthropic skills middleware

[sydney-runkle]

can ignore CC generated test file for now, needs lots of refining, but cool to play around with.

[codspeed-hq]

CodSpeed Performance Report

Merging #33555 will not alter performance

_{Comparing sr/anthropic-skills-middleware (856b877) with master (1d22735)}

Summary

✅ 3 untouched
⏩ 31 skipped¹

Footnotes

1. 31 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. ↩