Fix kargs module schema in BlueBuild recipe

The kargs module expects a `kargs` property (array of strings),
not `append`/`delete`. The `delete: [nomodeset]` is unnecessary
since nomodeset is not a default Fedora karg.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: SecAI-Hub

recipes/recipe.yml

@@ -69,7 +69,7 @@ modules:
 
   # 5) Kernel args: GPU setup + disable swap + security hardening.
   - type: kargs
-    append:
+    kargs:
       # NVIDIA
       - rd.driver.blacklist=nouveau
       - modprobe.blacklist=nouveau
@@ -88,8 +88,6 @@ modules:
       - zswap.enabled=0
       - lockdown=confidentiality
       - iommu=force
-    delete:
-      - nomodeset
 
   # 6) Enable/disable systemd units baked into the image.
   - type: systemd