fix(release): drop @semantic-release/git to satisfy main branch protection (#175)

The release CI was failing on the `prepare` step because
`@semantic-release/git` does `git push --tags HEAD:main` to commit the
`chore(release): X.Y.Z [skip ci]` bump back to main, and main has a
branch protection rule that requires PRs.

Concrete failure observed on the release run for #174:

  remote: error: GH013: Repository rule violations found for refs/heads/main.
  remote: - Changes must be made through a pull request.
  error: failed to push some refs to '.../deco-start.git'
  pluginName: '@semantic-release/git'

Result: prepare aborts, publish never runs, npm stays on the previous
version, no GitHub release is created.

Drop the @semantic-release/git plugin. We keep:
- @semantic-release/commit-analyzer (decides the next version)
- @semantic-release/release-notes-generator (CHANGELOG body)
- @semantic-release/exec — `npm version ${version} --no-git-tag-version`
  on prepare (mutates package.json *locally* in the runner before
  publish) and `npm publish` on publish
- @semantic-release/github (GitHub release + tag)

What changes in practice:
- npm still publishes the correct version (exec.prepareCmd runs first)
- GitHub release and tag still created (@semantic-release/github)
- package.json on main is NOT auto-bumped after each release. Source of
  truth for the current version becomes the git tag, not package.json.
- The "[skip ci]" suppression commit no longer happens — but the release
  workflow only triggers on push to main/next, and the publish job is
  the workflow itself, so there is no loop to suppress.

This is a deliberate tradeoff: keep the branch protection rule (which
is the intended safety net) and accept that package.json lags the tag.
Storefronts pin via npm version, so they're unaffected.

Co-authored-by: Claude Opus 4.7 <noreply@anthropic.com>

Author: JonasJesus42

.releaserc.json

@@ -23,10 +23,6 @@
       "prepareCmd": "npm version ${nextRelease.version} --no-git-tag-version",
       "publishCmd": "npm publish --access public --tag ${nextRelease.channel}"
     }],
-    "@semantic-release/github",
-    ["@semantic-release/git", {
-      "assets": ["package.json"],
-      "message": "chore(release): ${nextRelease.version} [skip ci]"
-    }]
+    "@semantic-release/github"
   ]
 }