docs: fix CHANGELOG structure so Release Please inserts above pre-release history

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

Author: locus313

CHANGELOG.md

@@ -4,12 +4,6 @@ All notable changes to this project will be documented in this file.
 
 This changelog is automatically maintained by [Release Please](https://github.com/googleapis/release-please) using [Conventional Commits](https://www.conventionalcommits.org/). Do not edit the versioned sections manually.
 
-<!-- Release Please inserts new entries above this line -->
-
----
-
-## Pre-release history
-
 ## 1.0.0 (2026-06-26)
 
 
@@ -52,6 +46,10 @@ This changelog is automatically maintained by [Release Please](https://github.co
 * open PR instead of pushing directly to protected main branch ([#14](https://github.com/locus313/github-api-scripts/issues/14)) ([37982f2](https://github.com/locus313/github-api-scripts/commit/37982f260b2b5306ca390c4f7e6b8fcdd1e40f8b))
 * update shebang from /bin/bash to /usr/bin/env bash in multiple scripts ([bcdc7db](https://github.com/locus313/github-api-scripts/commit/bcdc7dba96881a7e300746aac71a69de487b3ebd))
 
+---
+
+## Pre-release history
+
 ### 2026-06-26
 
 - feat: composite `action.yml` for all 16 automation scripts — each script is now usable as a `uses:` step in GitHub Actions workflows, enabling Dependabot to track and bump version pins automatically