debug: add anyio package inspection to CI

Add debugging step to lowest-direct tests to inspect the actual
anyio package being installed. This will help diagnose why the CI
is seeing code that tries to import RunFinishedError (which only
exists in anyio 4.11+) even though anyio 4.5.0 is being installed.

The debug step will output:
- Installed anyio version
- Package location
- Whether RunFinishedError appears in the source
- First 100 lines of _backends/_asyncio.py
- Package directory contents

This runs only on lowest-direct tests to avoid cluttering logs.

Author: felixweinberger

.github/workflows/shared.yml

@@ -56,6 +56,26 @@ jobs:
       - name: Install the project
         run: uv sync ${{ matrix.dep-resolution.install-flags }} --all-extras --python ${{ matrix.python-version }}
 
+      - name: Debug - Inspect installed anyio package
+        if: matrix.dep-resolution.name == 'lowest-direct'
+        run: |
+          set -x
+          echo "=== Anyio Version ==="
+          uv run python -c "from importlib.metadata import version; print(version('anyio'))"
+
+          echo "=== Anyio Package Location ==="
+          ANYIO_PATH=$(uv run python -c "import anyio, os; print(os.path.dirname(anyio.__file__))")
+          echo "$ANYIO_PATH"
+
+          echo "=== Checking for RunFinishedError in _asyncio.py ==="
+          grep -n "RunFinishedError" "$ANYIO_PATH/_backends/_asyncio.py" || echo "Not found"
+
+          echo "=== First 100 lines of _asyncio.py ==="
+          head -100 "$ANYIO_PATH/_backends/_asyncio.py"
+
+          echo "=== List anyio package contents ==="
+          ls -la "$ANYIO_PATH"
+
       - name: Run pytest
         run: uv run --frozen --no-sync pytest