chore: bump ext-apps to 1.7.3 (#680)

No SDK API changes since 1.7.2.

Examples:
- Add lazy-auth-server example (#679)
- Publish lazy-auth-server to npm (added to publish workflows)

Also syncs example dependency ranges to ^1.7.0 (output of npm run bump).

package.json

@@ -5,7 +5,7 @@
     "url": "https://github.com/modelcontextprotocol/ext-apps"
   },
   "homepage": "https://github.com/modelcontextprotocol/ext-apps",
-  "version": "1.7.2",
+  "version": "1.7.3",
   "license": "MIT",
   "description": "MCP Apps SDK — Enable MCP servers to display interactive user interfaces in conversational clients.",
   "type": "module",