Use pre-commit for Prettier in CI and document local hook setup.

Run prettier via pre-commit in code-quality workflow and add README instructions for installing and running hooks during development.

Co-authored-by: Cursor <[email protected]>

.gitea/workflows/code-quality.yml

@@ -39,6 +39,4 @@ jobs:
         run: uv run pyupgrade --py313-plus $(git ls-files '*.py') && git diff --exit-code
 
       - name: Prettier format
-        run: |
-          npm install --save-dev --save-exact prettier
-          npx prettier --check .
+        run: uv run pre-commit run prettier --all-files