fix(backend): use host config for dnf install to resolve repos

iridium_installer/backend/os_install.py

@@ -36,10 +36,12 @@ def install_minimal_os(mount_root, releasever="41"):
     
     # Fedora 41 (or whatever is current)
     # We use --releasever to ensure dnf knows which version to fetch
+    # We use --use-host-config because the installroot is initially empty and has no repo config
     cmd = [
         "dnf", "install", "-y",
         f"--installroot={mount_root}",
         f"--releasever={releasever}",
+        "--use-host-config",
         "--setopt=install_weak_deps=False",
         "--nodocs"
     ] + packages