Restrict coverage to include/ and src/ directories only

Anchor lcov extract patterns to */BehaviorTree.CPP/include/* and
*/BehaviorTree.CPP/src/* to avoid matching vendored 3rdparty code.
Add codecov.yml with server-side ignore rules for 3rdparty, examples,
sample_nodes, tests, and tools.

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

Author: facontidavide

.github/workflows/cmake_ubuntu.yml

@@ -86,8 +86,8 @@ jobs:
              --ignore-errors mismatch \
              --ignore-errors negative
         lcov --extract coverage.info \
-             '*/include/*' \
-             '*/src/*' \
+             '*/BehaviorTree.CPP/include/*' \
+             '*/BehaviorTree.CPP/src/*' \
              --output-file coverage.info \
              --ignore-errors unused
         lcov --list coverage.info

codecov.yml

@@ -0,0 +1,12 @@
+coverage:
+  status:
+    project:
+      default:
+        target: auto
+
+ignore:
+  - "3rdparty/**/*"
+  - "examples/**/*"
+  - "sample_nodes/**/*"
+  - "tests/**/*"
+  - "tools/**/*"