docs(fe): record backend/gateway data-flow contract in AGENTS.md

services/frontend/AGENTS.md

@@ -8,3 +8,29 @@ Key points:
 - **WebSocket** at `src/lib/ws/` — auto-reconnecting client with typed event subscriptions
 - **Static export**: `output: "export"` in next.config.ts, served via nginx
 - **No authentication**: all endpoints are public
+
+## Data flow (match these — do not invent endpoints)
+
+```
+Discord → discord-gateway → Redis pub/sub → backend (Express :3001) ←→ frontend
+                                                ↑ REST /api/*        (same-origin)
+                                                └ WS /ws (events + PCM binary)
+```
+
+- **Base URL**: API + WS default to same-origin. `gmw-proxy` nginx (:8080)
+  proxies `/api` and `/ws` to the backend on :3001. Public host:
+  `imphnen.asepharyana.my.id` (Cloudflare SSL in front of Traefik → :8080).
+- Local dev overrides: `NEXT_PUBLIC_API_URL` and `NEXT_PUBLIC_WS_URL`
+  (e.g. https://imphnen.asepharyana.my.id).
+- **Never hardcode a host** in api/ws clients — same-origin or env override only.
+
+## Backend response shapes that bite
+
+- `GET /api/chat/history` → `{ history: ChatbotHistoryRow[], total }` where
+  each row is `{ id, user_id, user_message, bot_response, context, created_at }`.
+  Map rows to display messages in `chatbot-context.tsx`.
+- `message_deleted` WS payload → `{ id, deleted_at }` (an object, not a string).
+- `voice_recording_uploaded` WS payload has **no** `duration_bytes` (REST rows do).
+- Dashboard endpoints: `/api/dashboard/stats|users|channels` (+ `/:id` details).
+- Channel/guild names live inside `message.metadata` JSON (`channel.channelName`),
+  not top-level.