docs: include code style/messaging guides

Author: mwfarb

CONTRIBUTING.md

@@ -9,3 +9,16 @@ This document covers **development rules and conventions** specific to this repo
 ### 1. Dependencies — Pin All Versions
 
 **All dependencies must use exact, pegged versions** (no `^`, `~`, or `*` ranges). This prevents version drift across environments and ensures reproducible builds for security.
+
+## Local Development
+
+To develop the `arena-account` locally:
+1. Run `init-config.sh` in the parent `arena-services-docker` directory to generate the required `.env` secrets and configuration files.
+2. Start the local stack using `docker-compose -f docker-compose.localdev.yaml up -d arena-account`
+3. The Django source folder is mounted via the localdev compose file. For testing or migrations, you can exec into the container and use `manage.py`.
+
+## Code Style
+- Follow standard Python formatting guidelines (`black` and `PEP 8`).
+- Ensure all HTTP handlers return standard JSON payloads.
+
+The `arena-account` uses [Release Please](https://github.com/googleapis/release-please) to automate CHANGELOG generation and semantic versioning. Your PR titles *must* follow Conventional Commit standards (e.g., `feat:`, `fix:`, `chore:`).