feat: enhance agent sharing functionality and UI improvements

- Added shared agents state management in Navigation and AgentsList components.
- Implemented fetching and displaying shared agents in the AgentsList.
- Introduced functionality to hide shared agents with appropriate API integration.
- Updated the SharedAgent component layout for better UI consistency.
- Improved error handling in conversation fetching logic.
- Added new API endpoint for hiding shared agents.
- Updated Redux slice to manage shared agents state.
- Refactored AgentCard and AgentSection components for better code organization and readability.

frontend/src/api/endpoints.ts

@@ -18,6 +18,7 @@ const endpoints = {
     SHARED_AGENT: (id: string) => `/api/shared_agent?token=${id}`,
     SHARED_AGENTS: '/api/shared_agents',
     SHARE_AGENT: `/api/share_agent`,
+    HIDE_SHARED_AGENT: (id: string) => `/api/hide_shared_agent?id=${id}`,
     AGENT_WEBHOOK: (id: string) => `/api/agent_webhook?id=${id}`,
     PROMPTS: '/api/get_prompts',
     CREATE_PROMPT: '/api/create_prompt',