Upgrade coverage to 7.15.4 for Python 3.14 CI support.

Older coverage.py releases corrupt trace data on Python 3.14, causing the coverage report to fail the 93% threshold even when all tests pass.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: sankalps0549

requirements.txt

@@ -1,6 +1,6 @@
 black==25.1.0
 build==1.2.2.post1
-coverage==7.6.12
+coverage==7.15.4
 docopt==0.6.2
 packaging==24.2
 pathspec==0.12.1