Some nice to have things before extension types work

[connortsui20]

Summary

Some setup work for #6618. Just want to make things easier before I try and resolve tens of merge conflicts in #6477

Testing

N/A

[codspeed-hq]

Merging this PR will improve performance by 10.94%

⚡ 1 improved benchmark
✅ 985 untouched benchmarks
⏩ 1426 skipped benchmarks¹

Performance Changes

	Mode	Benchmark	BASE	HEAD	Efficiency
⚡	Simulation	map_each[BufferMut<i32>, 128]	887.2 ns	799.7 ns	+10.94%

---

_{Comparing ct/ext-setup (a7f417c) with develop (ba7e329)}

Footnotes

1. 1426 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. ↩