feat: plugin skeleton for Shopware 6.6 and 6.7 with CI and release pipeline

- composer.json (MIT, shopware/core ~6.6.0 || ~6.7.0, PHP ^8.2), plugin class, placeholder icon
- PR checks and release workflow taken over from AeonDumpManager; phpunit runs as a 6.6/6.7 matrix
- CHANGELOG, LICENSE, README, CLAUDE.md, smoke test

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.config/shopware-extension.yml

@@ -0,0 +1,22 @@
+compatibility_date: 2026-02-11
+# shopware-cli extension configuration (build/package/validate)
+build:
+  zip:
+    pack:
+      excludes:
+        paths:
+          - tests
+          - docs
+          - scripts
+          - phpunit.xml
+          - docker-compose.yml
+          - skills-lock.json
+          - AGENTS.md
+          - CLAUDE.md
+          - QWEN.md
+          - .config
+          - .gitea
+          - .claude
+          - .scratch
+validation:
+  ignore: []