[FIX] Use uv tool install for tox instead of uv pip install

setup-uv v7 installs a uv-managed Python that isn't recognized as a
system Python. Use uv tool install which manages its own environment.

Author: jaseemjaskp

.github/workflows/ci-test.yaml

@@ -41,7 +41,7 @@ jobs:
             ${{ runner.os }}-tox-uv-
 
       - name: Install tox with UV
-        run: uv pip install --system tox tox-uv
+        run: uv tool install tox --with tox-uv
 
       - name: Run tox
         id: tox