feat(deploy): generate dishes before deploy and fix dish selection

- deploy.sh now runs 'make all' in cook/ before deploying, since dishes
  are build products no longer tracked in git; failures show the make
  output and abort
- deploy-distro.sh selects dishes by the *guest-agents* marker (the new
  naming replaced the virtual* prefix) and uses --os-variant
  fedora-unknown instead of the stale fedora41 pin

deploy.sh

@@ -11,6 +11,12 @@ execute_script() {
   return 0  # Indicate success
 }
 
+# Generate recipes and dishes before deployment (they are build products)
+if ! (cd cook && make all); then
+  echo "Failed to generate dishes in cook/ (see 'make all' in cook/)"
+  exit 1
+fi
+
 # Array of scripts
 scripts=(
   "./deploy/install-prerequisites-on-linux.sh"