# Task ID: 121

**Title:** Add AgentSession Prisma model

**Status:** pending

**Dependencies:** 118, 120

**Priority:** high

**Description:** Add AgentSession model with SessionState enum for ephemeral per-session pod tracking

**Details:**

In src/db/prisma/schema.prisma add:
1. enum SessionState { pending, provisioning, running, ended, failed }
2. model AgentSession with: id, agentId, projectId, taskId?, containerId?, state, image, expiresAt, lastError? (@db.Text), ownerId, createdAt, updatedAt, endedAt?
3. Relations: agent (Agent), project (Project), task (Task?), owner (User)
4. @@index([state]), @@index([taskId]), @@index([agentId])
5. Add sessions AgentSession[] to Agent, Project, Task, User models

**Test Strategy:**

Schema tests: create AgentSession with all relations, test cascade on Agent/Project delete, test SetNull on Task delete, verify state enum transitions.