CI: Consolidate python environment evaluation steps

* Format Code
* Combine cache type evaluation and installation verification into one
* Expose cache_type as output to invoked actions

Author: ByteOtter

.github/actions/setup/action.yml

@@ -1,45 +1,56 @@
 name: python_lib
 description: Installs the given GardenLinux Python library
+
 inputs:
-    version:
-        description: GardenLinux Python library version
-        default: "0.8.9"
+  version:
+    description: GardenLinux Python library version
+    default: "0.8.9"
+
+outputs:
+  version:
+    description: "Detected Python cache strategy."
+    value: ${{ steps.env-check.outputs.cache_type }}
+
 runs:
-    using: composite
-    steps:
-        - name: Verify requirements.txt for "actions/setup-python" with enabled "pip" cache
-          shell: bash
-          run: |
-            if [ ! -f "requirements.txt" ]; then
-                echo "python-gardenlinux-lib @ git+https://github.com/gardenlinux/python-gardenlinux-lib.git@${{ inputs.version }}" | tee -a requirements.txt
-            fi
-        - name: Check for Python
-          id: python-check
-          run: |
-            if command -v python &/dev/null; then
-              echo "python_installed=true" >> $GITHUB_OUTPUT
-            else
-              echo "python_installed=false" >> $GITHUB_OUTPUT
-            fi
-        - name: Activate caching based on lockfile
-          id: lockfile
-          run: |
-            if [ -f poetry.lock ]; then
-              echo "cache_type=poetry" >> $GITHUB_OUTPUT
-            elif [ -f requirements.txt ]; then
-              echo "cache_type=pip" >> $GITHUB_OUTPUT
-            else
-            # no lockfile present: create empty requirements.txt and use pip caching
-            touch requirements.txt
-            echo "cache_type=pip" >> $GITHUB_OUTPUT
-            fi
-        - name: Set up Python 3.13
-          if: steps.python-check.outputs.python_installed == 'false'
-          uses: actions/setup-python@v5
-          with:
-              python-version: "3.13"
-              cache: ${{ steps.lockfile.outputs.cache_type }}
-        - name: Install GardenLinux Python library
-          shell: bash
-          run: |
-              pip install git+https://github.com/gardenlinux/python-gardenlinux-lib.git@${{ inputs.version }}
+  using: composite
+  steps:
+    - name: Verify requirements.txt for "actions/setup-python" with enabled "pip" cache
+      shell: bash
+      run: |
+        if [ ! -f "requirements.txt" ]; then
+            echo "gardenlinux @ git+https://github.com/gardenlinux/python-gardenlinux-lib.git@${{ inputs.version }}" | tee -a requirements.txt
+        fi
+
+    - name: Evaluate Python Environment
+      id: env-check
+      shell: bash
+      run: |
+        # Check if python is installed
+        if command -v python &> /dev/null; then
+          echo "python_installed=true" >> $GITHUB_OUTPUT
+        else
+          echo "python_installed=false" >> $GITHUB_OUTPUT
+        fi
+
+        # Determine cache type based on available lockfile
+        if [ -f poetry.lock ]; then
+          echo "cache_type=poetry" >> $GITHUB_OUTPUT
+        elif [ -f requirements.txt ]; then
+          echo "cache_type=pip" >> $GITHUB_OUTPUT
+        else
+          # no lockfile present: create empty requirements.txt and use pip caching
+          touch requirements.txt
+          echo "cache_type=pip" >> $GITHUB_OUTPUT
+        fi
+
+    - name: Set up Python 3.13
+      if: steps.env-check.outputs.python_installed == 'false'
+      uses: actions/setup-python@v5
+      with:
+        python-version: "3.13"
+        cache: ${{ steps.env-check.outputs.cache_type }}
+
+    - name: Install GardenLinux Python library
+      shell: bash
+      run: |
+        pip install git+https://github.com/gardenlinux/python-gardenlinux-lib.git@${{ inputs.version }}