feat: Implement Plugin Marketplace Manager and Client

- Added PluginMarketplaceManager to coordinate marketplace reads and manage installed plugins.
- Introduced PluginMarketplaceClient for fetching marketplace metadata.
- Implemented storage management for installed plugins using MemoryStorage.
- Added methods for installing, uninstalling, and enabling/disabling plugins.
- Created type definitions for PluginMarketplaceManager options and installed plugin records.
- Added support for fetching full marketplace catalog and individual plugin metadata.
- Included error handling for fetch operations and validation of plugin data.
- Updated index.browser.ts to export new modules and types.

package.json

@@ -7,6 +7,7 @@
   "types": "./dist/index.d.ts",
   "exports": {
     ".": {
+      "browser": "./dist/index.browser.js",
       "import": "./dist/index.js",
       "types": "./dist/index.d.ts"
     }