ci: add test workflow to run Python and Node jobs

Add a Gitea workflow that runs on pull requests and pushes to main. It defines two jobs:
- Python: sets up Python 3.12, installs pytest, and runs language-server tests under server/tests/python_tests with PYTHONPATH=libs.
- Node: sets up Node 20, installs npm deps (root and client), runs extension tests (node --test test/) and builds the extension (npm run package).

Workflow file added at .gitea/workflows/tests.yml.

.gitea/workflows/tests.yml

@@ -0,0 +1,39 @@
+name: Tests
+on:
+    pull_request:
+    push:
+        branches: [main]
+jobs:
+    python:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - name: Install Python
+              uses: actions/setup-python@v5
+              with:
+                  python-version: "3.12"
+            - name: Install pytest
+              run: pip install pytest
+            - name: Run language server tests
+              working-directory: server
+              # The server's dependencies are bundled in server/libs.
+              env:
+                  PYTHONPATH: libs
+              run: python -m pytest tests/python_tests -q
+    node:
+        runs-on: ubuntu-latest
+        steps:
+            - uses: actions/checkout@v4
+            - name: Install NodeJS
+              uses: actions/setup-node@v4
+              with:
+                  node-version: 20
+            - name: Install NPM Packages
+              run: |
+                  npm ci
+                  cd ./client
+                  npm ci
+            - name: Run extension tests
+              run: node --test test/
+            - name: Build extension
+              run: npm run package