BC-250 console image: custom GNOME recipe with remote admin

Based on 62fixolab/Latest-Bazzite-AMD-BC-250-Patched-Images @ 347fd4d.

Adds on top of the fork:
- recipes/bc250-console-gnome.yml: governor + gnome-remote-desktop +
  openssh-server, sshd enabled, hhd.service masked, no signing module
  (local build + ISO path)
- files/console/usr/bin/bc250-remote-setup: one-time on-box SSH/RDP setup
- files/console/usr/lib/bootc/kargs.d/50-bc250-ttm.toml: ttm memory kargs
- BUILD-CONSOLE.md: build -> ISO -> validation instructions

files/console/ is separate from files/system/ so the 40-CU unlock tooling
stays out of this stable 24-CU image.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/backfill-releases.sh

@@ -0,0 +1,76 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+ROOT="$(git rev-parse --show-toplevel)"
+PUBLISH=0
+OWNER=""
+REPO=""
+
+usage() {
+  cat <<'EOF'
+Usage:
+  scripts/backfill-releases.sh [--publish]
+
+Creates local release-preview/*.md files for every date found in GHCR.
+With --publish, creates or updates one GitHub Release per date.
+EOF
+}
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    --publish)
+      PUBLISH=1
+      shift
+      ;;
+    --owner)
+      OWNER="${2:?Missing value for --owner}"
+      shift 2
+      ;;
+    --repo)
+      REPO="${2:?Missing value for --repo}"
+      shift 2
+      ;;
+    -h|--help)
+      usage
+      exit 0
+      ;;
+    *)
+      echo "Unknown argument: $1" >&2
+      usage >&2
+      exit 2
+      ;;
+  esac
+done
+
+if [[ -z "$OWNER" || -z "$REPO" ]]; then
+  OWNER="${OWNER:-$(gh repo view --json owner --jq '.owner.login')}"
+  REPO="${REPO:-$(gh repo view --json name --jq '.name')}"
+fi
+
+dates=()
+while IFS= read -r release_date; do
+  dates+=("$release_date")
+done < <("$ROOT/scripts/generate-release-notes.py" --owner "$OWNER" --repo "$REPO" --list-dates)
+
+for release_date in "${dates[@]}"; do
+  cmd=("$ROOT/scripts/publish-release.sh" --owner "$OWNER" --repo "$REPO" --date "$release_date")
+
+  package_commit="$(
+    "$ROOT/scripts/generate-release-notes.py" \
+      --owner "$OWNER" \
+      --repo "$REPO" \
+      --date "$release_date" \
+      --print-package-commit-tag
+  )"
+  if [[ -n "$package_commit" ]]; then
+    target_commit="$(git rev-parse --verify --quiet "${package_commit}^{commit}" || true)"
+    if [[ -n "$target_commit" ]]; then
+      cmd+=(--target "$target_commit")
+    fi
+  fi
+
+  if [[ "$PUBLISH" -eq 1 ]]; then
+    cmd+=(--publish)
+  fi
+  "${cmd[@]}"
+done