Update release agent: explicit PR steps for dev bump

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: bschnurr

.github/agents/release.agent.md

@@ -88,13 +88,18 @@ Goal: Keep `main` moving forward on an odd minor with `-dev` suffix.
    - From: the stable version just released (e.g. `2026.4.0` — *example*)
    - To: the next odd minor with `-dev` suffix (e.g. `2026.5.0-dev` — *example*)
 
-3. Commit, push, and merge via PR (replace `2026.5.0-dev` with the actual next dev version):
-   ```
-   git add package.json
-   git commit -m "Bump version to 2026.5.0-dev"
-   git push origin bump/2026.5.0-dev
+3. Commit and push (replace `2026.5.0-dev` with the actual next dev version):
+   ```
+   git add package.json
+   git commit -m "Bump version to 2026.5.0-dev"
+   git push origin bump/2026.5.0-dev
+   ```
+
+4. Create a PR targeting `main`, add the `debt` label, and enable auto-merge:
+   ```
+   gh pr create --base main --title "Bump version to 2026.5.0-dev" --body "Advance main to the next pre-release development version." --label debt
+   gh pr merge <PR_NUMBER> --squash --auto
    ```
-   Open a PR targeting `main` and merge it.
 
 > ✋ **Confirm**: Has `main` been updated to the next dev version?