Automate releases from PR titles and clean up CI workflows.

Add release and PR title checks, shared CI scripts, Gitea PR template, and align pyproject.toml to v0.3.1.

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

.gitea/workflows/code-quality.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version: ${{ inputs.python-version }}
+          python-version-file: .python-version
 
       - name: Install uv
         run: pip install uv
@@ -36,7 +36,7 @@ jobs:
         run: uv run ruff format --check .
 
       - name: Pyupgrade check
-        run: uv run pyupgrade --py313-plus $(git ls-files '*.py') && git diff --exit-code
+        run: uv run pyupgrade --py312-plus $(git ls-files '*.py') && git diff --exit-code
 
       - name: Prettier format
         run: uv run pre-commit run prettier --all-files