template-engine-copier skill: initial import

Copier + Jinja template-repository design skill: reference architecture,
implementation workflow, validation checklist, and a full worked example
template (questionnaire, extensions, resolvers, wrapper-first .scripts).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

example/copier-answers.example.yaml

@@ -0,0 +1,12 @@
+template_metadata:
+  domain: demo
+  project: sample-product
+
+features:
+  modules:
+    is_enabled: true
+    instances:
+      - name: users
+        version: 1.0.0
+      - name: billing
+        version: 1.0.0