feat(hooks): add auto-update-checker for plugin version management

Checks npm registry for latest version on session.created, invalidates
cache and shows toast notification when update is available.

🤖 GENERATED WITH ASSISTANCE OF [OhMyOpenCode](https://github.com/code-yeongyu/oh-my-opencode)

src/hooks/index.ts

@@ -11,4 +11,5 @@ export { createAnthropicAutoCompactHook } from "./anthropic-auto-compact";
 export { createThinkModeHook } from "./think-mode";
 export { createClaudeCodeHooksHook } from "./claude-code-hooks";
 export { createRulesInjectorHook } from "./rules-injector";
-export { createBackgroundNotificationHook } from "./background-notification";
+export { createBackgroundNotificationHook } from "./background-notification"
+export { createAutoUpdateCheckerHook } from "./auto-update-checker";