feat(sessions): add CreateSessionResponse type for better type safety

Introduce CreateSessionResponse type and schema to clearly define the return type of session creation operations. This improves type safety and consistency across the codebase when handling session responses.

src/main/apiServer/routes/agents/handlers/sessions.ts

@@ -1,5 +1,6 @@
 import { loggerService } from '@logger'
 import { sessionMessageService, sessionService } from '@main/services/agents'
+import { CreateSessionResponse } from '@types'
 import { Request, Response } from 'express'
 
 const logger = loggerService.withContext('ApiServerSessionsHandlers')
@@ -12,7 +13,7 @@ export const createSession = async (req: Request, res: Response): Promise<Respon
     logger.info(`Creating new session for agent: ${agentId}`)
     logger.debug('Session data:', sessionData)
 
-    const session = await sessionService.createSession(agentId, sessionData)
+    const session = (await sessionService.createSession(agentId, sessionData)) satisfies CreateSessionResponse
 
     logger.info(`Session created successfully: ${session.id}`)
     return res.status(201).json(session)