Replace symlink approach with rm -rf to prune Codecov file discovery

The symlinked root_dir broke path resolution — Codecov maps coverage
paths against the git repo, not the network root. Instead, simply
delete unwanted directories before upload so Codecov never sees them.

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

Author: facontidavide

.github/workflows/cmake_ubuntu.yml

@@ -96,28 +96,20 @@ jobs:
              --ignore-errors unused
         lcov --list coverage.info
 
-    - name: Prepare coverage source tree
+    - name: Prune directories from Codecov file discovery
       run: |
-        # Build a clean source tree with only the directories we want
-        # Codecov to see, excluding contrib/ and flatbuffers/
-        mkdir -p codecov_root/include/behaviortree_cpp
-        ln -s "$PWD/src" codecov_root/src
-        for item in include/behaviortree_cpp/*; do
-          name=$(basename "$item")
-          case "$name" in
-            contrib|flatbuffers) continue ;;
-          esac
-          ln -s "$PWD/$item" "codecov_root/include/behaviortree_cpp/$name"
-        done
-        # Rewrite absolute paths in coverage.info to be relative to codecov_root
-        sed -i "s|$PWD/||g" coverage.info
+        # Remove directories we don't want Codecov to discover as source files.
+        # Coverage data for these was already stripped by lcov above.
+        rm -rf examples sample_nodes tests tools \
+               include/behaviortree_cpp/contrib \
+               include/behaviortree_cpp/flatbuffers \
+               3rdparty
 
     - name: Upload coverage reports to Codecov
       uses: codecov/codecov-action@v5
       with:
         files: coverage.info
         flags: unittests
         disable_search: true
-        root_dir: codecov_root
         plugins: noop
         token: ${{ secrets.CODECOV_TOKEN }}