Exclude contrib/ vendored headers from coverage

Add lcov --remove for */contrib/* after extraction, and add
include/**/contrib/**/* to codecov.yml ignore list.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: facontidavide

.github/workflows/cmake_ubuntu.yml

@@ -90,6 +90,10 @@ jobs:
              '*/BehaviorTree.CPP/src/*' \
              --output-file coverage.info \
              --ignore-errors unused
+        lcov --remove coverage.info \
+             '*/contrib/*' \
+             --output-file coverage.info \
+             --ignore-errors unused
         lcov --list coverage.info
 
     - name: Upload coverage reports to Codecov

codecov.yml

@@ -7,6 +7,7 @@ coverage:
 ignore:
   - "3rdparty/**/*"
   - "examples/**/*"
+  - "include/**/contrib/**/*"
   - "sample_nodes/**/*"
   - "tests/**/*"
   - "tools/**/*"