[Zethson]

Adds the LLM usage section from scverse/pertpy#1165 to the PR template, asking which LLM or coding agent was used and confirming every changed line was reviewed, understood and tested by the author.
It links the scverse AI policy and states that PRs skipping the section are closed without review.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.79%. Comparing base (a26bc21) to head (26b0525).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2691      +/-   ##
==========================================
- Coverage   87.62%   85.79%   -1.84%     
==========================================
  Files          49       49              
  Lines        8138     8138              
==========================================
- Hits         7131     6982     -149     
- Misses       1007     1156     +149     

see 8 files with indirect coverage changes