Add dedicated lint job to CI with format and style checks

Splits linting out of the test matrix into its own single job.
Checks Python formatting (ruff format), Python linting (ruff check),
Markdown formatting (mdformat), and shell formatting (shfmt).

Author: jackjennings

.github/workflows/test.yml

@@ -7,6 +7,29 @@ on:
     branches: [main]
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+
+      - name: Install dependencies
+        run: uv sync
+
+      - name: Check Python formatting
+        run: uv run ruff format --check .
+
+      - name: Lint Python
+        run: uv run ruff check .
+
+      - name: Check Markdown formatting
+        run: uv run mdformat --check .
+
+      - name: Check shell formatting
+        run: shfmt -d .
+
   test:
     runs-on: ubuntu-latest
     strategy:
@@ -26,6 +49,3 @@ jobs:
 
       - name: Run tests
         run: uv run pytest tests
-
-      - name: Run linter
-        run: uv run ruff check .