refactor: divide agent logic and gateway into different package (#90)

* feat: add @memoh/agent

* chore: use @memoh/agent in @memoh-gateway

agent/src/models.ts

@@ -1,5 +1,5 @@
 import z from 'zod'
-import { allActions } from './types'
+import { allActions } from '@memoh/agent'
 
 export const AgentSkillModel = z.object({
   name: z.string().min(1, 'Skill name is required'),