fix: exclude CHANGELOG.md from Prettier formatting

- Remove auto-format workflow that was causing CI failures
- Add CHANGELOG.md to .prettierignore since it's managed by Release Please
- Update format scripts to use .prettierignore

This prevents formatting conflicts with Release Please's changelog updates.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: scottlovegrove

.github/workflows/format-release-pr.yml

@@ -1,2 +1,5 @@
 # ignore auto-generated documentation website
-website
+website
+
+# Exclude CHANGELOG.md as it's managed by Release Please
+CHANGELOG.md

.prettierignore

@@ -23,8 +23,8 @@
     },
     "scripts": {
         "clean": "rimraf dist",
-        "format-check": "npx prettier --check \"./**/*.{ts,tsx,json,md,yml,babelrc,html}\"",
-        "format-fix": "npx prettier --write \"./**/*.{ts,tsx,json,md,yml,babelrc,html}\"",
+        "format-check": "npx prettier --check \"./**/*.{ts,tsx,json,md,yml,babelrc,html}\" --ignore-path .prettierignore",
+        "format-fix": "npx prettier --write \"./**/*.{ts,tsx,json,md,yml,babelrc,html}\" --ignore-path .prettierignore",
         "lint": "eslint ./src --ext ts,tsx --fix",
         "lint-check": "eslint ./src --ext ts,tsx",
         "ts-compile-check": "npx tsc -p tsconfig.typecheck.json",