feat(agent): event timeline API, SSE stream, Coolify DDL, env template

- Add agent_session_events table + GET/POST events + SSE stream routes
- Build Agent tab: hydrate from events + EventSource while running
- entrypoint: create agent_sessions + agent_session_events on container start
- .env.example for AGENT_RUNNER_URL, AGENT_RUNNER_SECRET, DATABASE_URL

Made-with: Cursor

app/api/admin/migrate/route.ts

@@ -90,6 +90,20 @@ export async function POST(req: NextRequest) {
     `CREATE INDEX IF NOT EXISTS agent_sessions_project_idx ON agent_sessions (project_id, created_at DESC)`,
     `CREATE INDEX IF NOT EXISTS agent_sessions_status_idx ON agent_sessions (status)`,
 
+    `CREATE TABLE IF NOT EXISTS agent_session_events (
+      id BIGSERIAL PRIMARY KEY,
+      session_id UUID NOT NULL REFERENCES agent_sessions(id) ON DELETE CASCADE,
+      project_id TEXT NOT NULL,
+      seq INT NOT NULL,
+      ts TIMESTAMPTZ NOT NULL,
+      type TEXT NOT NULL,
+      payload JSONB NOT NULL DEFAULT '{}'::jsonb,
+      client_event_id UUID UNIQUE,
+      created_at TIMESTAMPTZ NOT NULL DEFAULT now(),
+      UNIQUE(session_id, seq)
+    )`,
+    `CREATE INDEX IF NOT EXISTS agent_session_events_session_seq_idx ON agent_session_events (session_id, seq)`,
+
     // NextAuth / Prisma tables
     `CREATE TABLE IF NOT EXISTS users (
       id             TEXT PRIMARY KEY,