chore: bump astral-sh actions to latest major versions

ruff-action v3 → v4, setup-uv v7 → v8

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

.github/workflows/lint.yml

@@ -26,7 +26,7 @@ jobs:
         uses: actions/checkout@v6
 
       - name: Run Ruff
-        uses: astral-sh/ruff-action@v3
+        uses: astral-sh/ruff-action@v4
         with:
           args: "check"