refactor: move Conan patching to separate action

- Create new xahau-patch-conan-clang-versions action
- Remove patching logic from dependencies action
- Call patch action after Conan initialization in main workflow
- Fixes sequencing issue where settings.yml didn't exist yet

.github/workflows/xahau-ga-nix.yml

@@ -250,6 +250,11 @@ jobs:
           # Display profile for verification
           conan profile show default
 
+      - name: Patch Conan for newer Clang versions
+        uses: ./.github/actions/xahau-patch-conan-clang-versions
+        with:
+          compiler-id: ${{ matrix.compiler_id }}
+
       - name: Check environment
         run: |
           echo "PATH:"