ci: add notify-failure, pytest with coverage, and 49 unit tests

- lint.yml: add notify-failure Matrix alert job
- test.yml: new workflow running pytest with pytest-cov for coverage
- .coveragerc: omit tests and site-packages from coverage
- .gitignore: ignore __pycache__ and .pyc files
- tests/test_hwmon.py: 49 unit tests covering SystemHealthMonitor
  (temperature parsing, service monitoring, disk usage, metric collection,
  dry run behaviour); uses unittest.mock to isolate from env/filesystem

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/test.yml

@@ -0,0 +1,23 @@
+name: Test
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  pytest:
+    name: Python Tests (pytest)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install Python and dependencies
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq python3 python3-pip python3-pytest python3-psutil python3-requests
+          pip3 install pytest-cov
+
+      - name: Run pytest with coverage
+        run: python3 -m pytest tests/ -v --cov=. --cov-report=term-missing --cov-config=.coveragerc