docs: add repository agent rules

Document the main-based branch flow and package delivery constraints for automated repository work.

Ref: IT-1033

AGENTS.md

@@ -0,0 +1,26 @@
+# HrynCo.RabbitMq Agent Rules
+
+## Git workflow
+
+- Treat `main` as the only default and integration branch for this repository.
+- Start every task branch from the latest `origin/main`.
+- Before creating a task branch, fetch the remote, switch to `main`, and fast-forward it from `origin/main`.
+- Create the task branch only after confirming that local `main` matches `origin/main`.
+- Open pull requests from the task branch into `main`.
+- Do not use `development` as the base or pull-request target for new work in this repository.
+- Do not commit, push, publish a NuGet package, or merge unless the repository owner explicitly requests that step.
+
+Recommended branch preparation:
+
+```text
+git fetch origin
+git switch main
+git pull --ff-only origin main
+git switch -c <task-branch>
+```
+
+## Delivery
+
+- Keep changes focused and backward compatible where practical because this repository produces a shared NuGet package.
+- Run the solution tests before handoff.
+- Use Conventional Commit messages with a lowercase subject and finish the commit body with `Ref: <issue-id>` when an issue exists.