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>

scripts/protect-main.sh

@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+# One-time (re-runnable) setup: require the PR checks on `main` using the Gitea `tea` CLI.
+# `tea branches protect` cannot set status-check contexts, hence `tea api`.
+# Usage: scripts/protect-main.sh [owner/repo]   (default: derived from the git remote)
+set -euo pipefail
+
+REPO="${1:-$(git config --get remote.origin.url | sed -E 's#^.*[:/]([^/]+/[^/]+)$#\1#; s#\.git$##')}"
+
+tea api -X PATCH "repos/${REPO}/branch_protections/main" -d '{
+  "enable_status_check": true,
+  "status_check_contexts": [
+    "plugin-checks / version-changelog (pull_request)",
+    "plugin-checks / package (pull_request)",
+    "plugin-checks / phpunit (6.6) (pull_request)",
+    "plugin-checks / phpunit (6.7) (pull_request)"
+  ]
+}'