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/.scripts/copier/lib/answers/-previous-pull-and-merge.sh

@@ -0,0 +1,6 @@
+#!/bin/bash
+
+_copier_answers_previous_pull_and_merge() {
+  local PREVIOUS="${HL_V1_COPIER_TARGET_DIR}/${HL_V1_COPIER_FILE_COPIER_ANSWERS}"
+  [ -f "${PREVIOUS}" ] && cp "${PREVIOUS}" "${HL_V1_COPIER_FILE_COPIER_ANSWERS_NEW}" || true
+}