Restore ci/build_docs.sh and fern/** exclusions in changed-files groups

Changes to ci/build_docs.sh should not trigger test_cpp, test_python_conda,
or test_python_wheels. Replace the old !docs/** exclusion (Sphinx tree, now
deleted) with !fern/** in test_cpp and test_python_conda so Fern-only changes
don't trigger those test suites.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Ramakrishna Prabhu <ramakrishnap@nvidia.com>

Author: ramakrishnap-nv

.github/workflows/pr.yaml

@@ -174,6 +174,7 @@ jobs:
           - '!README.md'
           - '!SECURITY.md'
           - '!agents/**'
+          - '!ci/build_docs.sh'
           - '!ci/build_python.sh'
           - '!ci/build_wheel*.sh'
           - '!ci/check_style.sh'
@@ -186,6 +187,7 @@ jobs:
           - '!ci/utils/sync_skills_version.sh'
           - '!ci/utils/validate_skills.sh'
           - '!container-builder/**'
+          - '!fern/**'
           - '!gemini-extension.json'
           - '!helmchart/**'
           - '!img/**'
@@ -242,6 +244,7 @@ jobs:
           - '!README.md'
           - '!SECURITY.md'
           - '!agents/**'
+          - '!ci/build_docs.sh'
           - '!ci/build_wheel*.sh'
           - '!ci/check_style.sh'
           - '!ci/docker/**'
@@ -252,6 +255,7 @@ jobs:
           - '!ci/utils/sync_skills_version.sh'
           - '!ci/utils/validate_skills.sh'
           - '!container-builder/**'
+          - '!fern/**'
           - '!gemini-extension.json'
           - '!helmchart/**'
           - '!img/**'
@@ -308,6 +312,7 @@ jobs:
           - '!SECURITY.md'
           - '!agents/**'
           - '!ci/build_cpp.sh'
+          - '!ci/build_docs.sh'
           - '!ci/build_python.sh'
           - '!ci/check_style.sh'
           - '!ci/docker/**'