chore: add Renovate configuration and workflows

- Introduced .renovaterc for Renovate settings.
- Added renovate.config.cjs for Gitea integration.
- Created .gitea/workflows/renovate.yml for daily Renovate runs.
- Added .gitea/workflows/test.yml for CI testing.
- Removed outdated GitHub workflows and configuration files.

.gitea/workflows/test.yml

@@ -0,0 +1,16 @@
+name: Test
+
+on: [push, pull_request]
+
+jobs:
+  test:
+    name: npm test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 22
+      - run: npm ci
+      - run: npm run check
+      - run: npm run typecheck