Docs: Update Git and PR conventions

- Restructure Git conventions into sub-sections for better organization
- Add a new convention to exclude test plans from PR descriptions

docs/agents/core.md

@@ -69,12 +69,16 @@ ResInsight includes Python integration via gRPC when `RESINSIGHT_ENABLE_GRPC=ON`
 - Third-party dependencies: `ThirdParty/` with individual CMakeLists.txt files
 - Python API: `GrpcInterface/Python/`
 
-## Git Commit Conventions
+## Git
 
+### Commit Conventions
 - When creating a git commit for a feature request use the issue number at the start of the title, e.g "#12773 Python: Add API for creating valve templates"
 - When creating a commit use git conventions
 - Always run python formatting/check on changed files before commits
 
+### PR Conventions
+- Do not include a test plan in the PR description
+
 ## Making PDM Objects Scriptable for Python GRPC Interface
 
 To make a PDM (Project Data Model) object available in the Python GRPC interface, you need to make it "scriptable":