manifest: list coa-template (include:false; template repo, not an addon)

manifest.yaml

@@ -10,6 +10,10 @@ addons:
     include: false
     note: "Ace3 libs are already embedded inside each consuming fork; the pack doesn't need them again."
 
+  - repo: coa-template             # template-only — not an installable addon
+    include: false
+    note: "Gitea "Use This Template" source repo for new coa-* forks."
+
   - repo: coa-ai-voiceover
     include: true