ci: require the AI-Assisted tag only on commits done after 2026

[gpotter2]

See #5002 (comment)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 80.28%. Comparing base (65816b7) to head (5656252).
⚠️ Report is 1 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5004      +/-   ##
==========================================
- Coverage   80.28%   80.28%   -0.01%     
==========================================
  Files         383      383              
  Lines       95159    95159              
==========================================
- Hits        76402    76396       -6     
- Misses      18757    18763       +6     

see 5 files with indirect coverage changes

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