chore: release 0.3.0 (#204)

* chore: bump version to 0.3.0

Breaking changes:
- `viewport` replaced with `containerDimensions` in host context

New examples:
- video-resource-server
- sheet-music-server

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

* fix(video-resource-server): add missing server-utils and fix import path

The video-resource-server was importing from a non-existent
../shared/server-utils.js path. Added the server-utils.ts file
and fixed the import to use ./src/server-utils.js like other examples.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

* chore: update ext-apps version refs to 0.3.0

---------

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

examples/basic-server-react/package.json

@@ -24,7 +24,7 @@
     "prepublishOnly": "npm run build"
   },
   "dependencies": {
-    "@modelcontextprotocol/ext-apps": "^0.2.2",
+    "@modelcontextprotocol/ext-apps": "^0.3.0",
     "@modelcontextprotocol/sdk": "^1.24.0",
     "react": "^19.2.0",
     "react-dom": "^19.2.0",