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>

recipes/bc250-console-gnome.yml

@@ -0,0 +1,40 @@
+---
+# yaml-language-server: $schema=https://schema.blue-build.org/recipe-v1.json
+name: bc250-console-gnome
+description: BC-250 couch gaming console — Bazzite GNOME with cyan-skillfish GPU governor, remote admin (SSH + GNOME Remote Desktop), and BC-250 ttm kernel args.
+
+base-image: ghcr.io/ublue-os/bazzite-gnome
+image-version: stable
+
+modules:
+  - type: rpm-ostree
+    repos:
+      - https://copr.fedorainfracloud.org/coprs/filippor/bazzite/repo/fedora-%OS_VERSION%/filippor-bazzite-fedora-%OS_VERSION%.repo
+    install:
+      - cyan-skillfish-governor-smu
+      - gnome-remote-desktop # RDP GUI (installing games via Steam)
+      - openssh-server # headless admin (updates, shell)
+
+  # files/console/ only — files/system/ holds the 40-CU unlock tooling,
+  # which stays out of this stable 24-CU console image.
+  - type: files
+    files:
+      - source: console
+        destination: /
+
+  - type: script
+    snippets:
+      - chmod 0755 /usr/bin/bc250-remote-setup
+
+  - type: systemd
+    system:
+      enabled:
+        - cyan-skillfish-governor-smu.service
+        - sshd.service
+      masked:
+        - hhd.service # Handheld Daemon crash-loops on BC-250
+
+  # No signing module: this image is built locally and installed via ISO.
+  # If you ever push to a registry for OTA `bootc upgrade`, generate your own
+  # cosign keypair (do NOT reuse upstream's cosign.pub) and re-add:
+  #   - type: signing