Fix npm provenance failure and bump version to 2.1.1

[pxlarified]

Why

The Release workflow's Publish to npm step failed with E422 (run 28901148005):

npm error 422 Unprocessable Entity - PUT https://registry.npmjs.org/@pxlarified%2fbrowser
Error verifying sigstore provenance bundle: Failed to validate repository information:
package.json: "repository.url" is "git+https://github.com/mizius-studios/OpenBrowser.git",
expected to match "https://github.com/miziusLabs/OpenBrowser" from provenance

npm publish --provenance requires package.json repository.url to match the GitHub repository the build actually ran in. The value still pointed at the old mizius-studios/OpenBrowser slug, while the workflow runs in miziusLabs/OpenBrowser, so npm rejected the signed provenance bundle. Nothing was published (the request 422'd before upload).

Changes

1. Correct repository.url to the current repo, using the normalized git+https://...git form (also clears the npm warn publish ... run "npm pkg fix" warning seen in the same log):

   "repository": {
     "type": "git",
     "url": "git+https://github.com/miziusLabs/OpenBrowser.git"
   }

2. Bump version 2.1.0 -> 2.1.1 so merging this triggers a fresh release.

Release behavior

The Release workflow only publishes when its Detect version bump step sees a changed package.json version, and it checks out main. On merge it will detect 2.1.0 -> 2.1.1, run sync:version to propagate the version into extensions/manifest.json and the README badge, and publish 2.1.1 to npm with matching provenance.