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/projects/[projectId]/agent/sessions/[sessionId]/retry/route.ts

@@ -66,6 +66,13 @@ export async function POST(
     );
     const giteaRepo = proj[0]?.data?.giteaRepo as string | undefined;
 
+    // Clear persisted event timeline so SSE / replay matches the new run (no-op if table missing)
+    try {
+      await query(`DELETE FROM agent_session_events WHERE session_id = $1::uuid`, [sessionId]);
+    } catch {
+      /* table may not exist until admin migrate */
+    }
+
     // Reset the session row so the frontend shows it as running again
     await query(
       `UPDATE agent_sessions