refactor: break monorepo into 3 standalone services (gateway, backend, frontend)

- Remove pnpm workspace, moon repo, and all monorepo tooling
- Delete packages/shared/, embed shared code directly into each service
- Copy packages/shared/src/* -> services/backend/src/shared/ and services/discord-gateway/src/shared/
- Replace all @bete/shared imports with @/shared/ path alias
- Remove @bete/shared workspace dependency from both services
- Update root package.json scripts from --filter to --prefix
- Rewrite Dockerfiles to build each service standalone
- Clean up biome.json, .gitignore, remove root drizzle.config.ts

services/backend/src/ws/broadcast.ts

@@ -9,7 +9,7 @@
  *   broadcastEvent("message_created", messageData);
  */
 
-import { createChildLogger } from "@bete/shared/logger";
+import { createChildLogger } from "@/shared/logger/index";
 
 const logger = createChildLogger("broadcast");
 

services/backend/src/ws/redis-bridge.ts

@@ -1,5 +1,5 @@
-import { DISCORD_CHANNEL_TO_WS_EVENT, DISCORD_VOICE_PCM } from "@bete/shared";
-import { createChildLogger } from "@bete/shared/logger";
+import { DISCORD_CHANNEL_TO_WS_EVENT, DISCORD_VOICE_PCM } from "../shared/index.js";
+import { createChildLogger } from "../shared/logger/index.js";
 import Redis from "ioredis";
 import { config } from "../shared/config/index.js";
 import { broadcastBinary, broadcastEvent } from "./broadcast.js";

services/backend/src/ws/server.ts

@@ -1,6 +1,6 @@
 import type { Server } from "node:http";
-import { BACKEND_COMMAND, BACKEND_VOICE_TRANSMIT } from "@bete/shared";
-import { createChildLogger } from "@bete/shared/logger";
+import { BACKEND_COMMAND, BACKEND_VOICE_TRANSMIT } from "../shared/index.js";
+import { createChildLogger } from "../shared/logger/index.js";
 import { WebSocket, WebSocketServer } from "ws";
 import { config } from "../shared/config/index.js";
 import { setBroadcastFunctions } from "./broadcast.js";