chore: add warning for native runner

[jaychia]

No description provided.

[codspeed-hq]

CodSpeed Performance Report

Merging #3613 will improve performances by 62.63%

_{Comparing jay/warn-native (b88705e) with main (5e40837)}

Summary

⚡ 2 improvements
✅ 25 untouched benchmarks

Benchmarks breakdown

	Benchmark	main	jay/warn-native	Change
⚡	test_count[1 Small File]	3.9 ms	3.3 ms	+19.04%
⚡	test_iter_rows_first_row[100 Small Files]	332.8 ms	204.6 ms	+62.63%

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 77.81%. Comparing base (5e40837) to head (b88705e).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #3613   +/-   ##
=======================================
  Coverage   77.81%   77.81%           
=======================================
  Files         718      718           
  Lines       88249    88252    +3     
=======================================
+ Hits        68667    68674    +7     
+ Misses      19582    19578    -4     

Files with missing lines	Coverage Δ
daft/context.py	87.65% <100.00%> (+0.07%)	⬆️

... and 2 files with indirect coverage changes