docs: match CLAUDE.md to the idempotent release and registry repack

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

CLAUDE.md

@@ -80,9 +80,10 @@ means fix the config.
   (shared composite action `actions/package`: `shopware-cli extension package`, `extension validate` on
   the zip, `scripts/ci/assert-built-assets.sh`), and `phpunit`. The package job caches the tested zip
   keyed by the commit's tree hash.
-- `workflows/release.yml` (push to `main`, serialized, skipped if tag `v<version>` exists): reuses the
+- `workflows/release.yml` (push to `main`, serialized; every step is idempotent so a failed run can simply be re-run): reuses the
   cached zip when the tree hash matches (else packages again, always re-validates), creates the Gitea
-  release + tag via API with the zip as asset, publishes to the Composer registry, then links the
+  release + tag via API with the zip as asset, publishes a root-level repack of the zip to the Composer registry
+  (Gitea requires `composer.json` at the zip root), then links the
   package to the repo. Uses `RELEASE_TOKEN`.
 - Required checks on `main` (`plugin-checks / version-changelog|package|phpunit (pull_request)`) are set
   once with `scripts/protect-main.sh` (`tea api`). Build excludes/validation live in