feat: refactor context usage and add search template route

- Updated context key usage from `useConfigKey` to `useContextKey` in app initialization.
- Introduced a new route for searching templates related to 小红书 with a default keyword.
- Enhanced error handling for saving notes and user information.
- Added a command for searching templates in the CLI.
- Created a new agent plugin for browser integration.

.opencode/plugin/agent.ts

@@ -0,0 +1,3 @@
+import { browserAgentPlugin } from './../../src/index.ts';
+
+export { browserAgentPlugin }