Fix Codecov UI showing files outside include/ and src/

Codecov's ignore directive only affects status checks, not the file tree
display. Add paths restrictions via flags and coverage.status.project to
limit reporting scope, and disable_search to prevent auto-discovery of
extra coverage files.

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

Author: facontidavide

.github/workflows/cmake_ubuntu.yml

@@ -100,4 +100,6 @@ jobs:
       uses: codecov/codecov-action@v5
       with:
         files: coverage.info
+        flags: unittests
+        disable_search: true
         token: ${{ secrets.CODECOV_TOKEN }}

codecov.yml

@@ -3,11 +3,20 @@ coverage:
     project:
       default:
         target: auto
+        paths:
+          - "include/behaviortree_cpp/**"
+          - "src/**"
+
+flags:
+  unittests:
+    paths:
+      - "include/behaviortree_cpp/**"
+      - "src/**"
 
 ignore:
-  - "3rdparty/**/*"
-  - "examples/**/*"
-  - "include/**/contrib/**/*"
-  - "sample_nodes/**/*"
-  - "tests/**/*"
-  - "tools/**/*"
+  - "3rdparty/**"
+  - "examples/**"
+  - "include/**/contrib/**"
+  - "sample_nodes/**"
+  - "tests/**"
+  - "tools/**"