fix(ci): use --allow-existing flag for uv venv (#24)

When the virtual environment cache is restored, the .venv directory
already exists, causing `uv venv` to fail. The --allow-existing flag
allows uv to reuse or recreate the venv as needed.

Co-authored-by: Ambient Code <ambient-code@redhat.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

Author: 3 people

.github/workflows/ci.yml

@@ -35,7 +35,7 @@ jobs:
             venv-${{ runner.os }}-
 
       - name: Create virtual environment
-        run: uv venv
+        run: uv venv --allow-existing
 
       - name: Install dependencies
         run: uv pip install -e ".[dev]"