docs: higher quality daft diagram for readme

[ccmao1130]

No description provided.

[codspeed-hq]

CodSpeed Performance Report

Merging #3697 will degrade performances by 28.66%

_{Comparing daft-diagram (7e130e3) with main (e7abec3)}

Summary

❌ 1 regressions
✅ 26 untouched benchmarks

⚠️ Please fix the performance issues or acknowledge them on CodSpeed.

Benchmarks breakdown

	Benchmark	main	daft-diagram	Change
❌	test_iter_rows_first_row[100 Small Files]	164.2 ms	230.2 ms	-28.66%

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.97%. Comparing base (e7abec3) to head (7e130e3).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3697      +/-   ##
==========================================
- Coverage   77.89%   76.97%   -0.92%     
==========================================
  Files         721      719       -2     
  Lines       90422    91419     +997     
==========================================
- Hits        70434    70371      -63     
- Misses      19988    21048    +1060     

see 26 files with indirect coverage changes