Build Fedora aarch64 images for the Lenovo Yoga C630

Assembles a ready-to-write disk image via Gitea Actions. Mainline has carried
sdm850-lenovo-yoga-c630.dts since 5.5 and Fedora ships it in kernel-core, so
unlike aarch64-laptops/build there is no kernel or GRUB to compile — what is
left is producing an image that boots on firmware which hands Linux no device
tree.

The build runs in an aarch64 container under qemu-user and builds filesystems
from directory trees with mke2fs -d and mcopy rather than mounting loop
devices, so it works on runners that will not hand out /dev/loop-control.

A kernel-install hook writes the devicetree line into each BLS entry; without
it the first `dnf update kernel` would produce an unbootable system.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XWRjNJMistCy6ngXH5aJLS

.gitea/workflows/probe-runner.yaml

@@ -0,0 +1,44 @@
+name: probe runner
+
+# Run this once by hand to find out what the runners can actually do before
+# blaming the build for failing. It changes nothing.
+on:
+  workflow_dispatch:
+
+jobs:
+  probe:
+    runs-on: metal
+    steps:
+      - name: Identity and privileges
+        run: |
+          echo "runner name : ${RUNNER_NAME:-?}"
+          echo "arch        : $(uname -m)"
+          echo "kernel      : $(uname -r)"
+          echo "os          : $(. /etc/os-release && echo "$PRETTY_NAME")"
+          echo "user        : $(id -un) uid=$(id -u)"
+          echo -n "passwordless sudo : "
+          sudo -n true 2>/dev/null && echo yes || echo no
+
+      - name: Container tooling
+        run: |
+          echo -n "podman  : "; podman --version 2>/dev/null || echo MISSING
+          echo -n "rootless: "; podman info --format '{{.Host.Security.Rootless}}' 2>/dev/null || echo '?'
+          echo "storage : $(podman info --format '{{.Store.GraphRoot}}' 2>/dev/null || echo '?')"
+
+      - name: Emulation
+        run: |
+          if [ -e /proc/sys/fs/binfmt_misc/qemu-aarch64 ]; then
+            cat /proc/sys/fs/binfmt_misc/qemu-aarch64
+          else
+            echo "no aarch64 binfmt handler registered"
+          fi
+
+      - name: Can we actually run an aarch64 container?
+        continue-on-error: true
+        run: |
+          podman run --rm --arch arm64 registry.fedoraproject.org/fedora:44 \
+            bash -c 'echo "inside: $(uname -m)"; rpm --eval %{_arch}'
+
+      - name: Disk space
+        run: |
+          df -h / /var /tmp . 2>/dev/null | sort -u