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/{{ '.tmp-gitlab-ci.yml' }}.jinja

@@ -0,0 +1,17 @@
+stages:
+  - lint
+  - test
+
+template-content-check:
+  stage: lint
+  image: alpine:3.20
+  script:
+    - test -f README.md
+    - test -f copier-answers.example.yaml
+    - test -d src
+
+template-smoke-test:
+  stage: test
+  image: alpine:3.20
+  script:
+    - echo "Template repository scaffold is present"