fix(build): make oRPC/tRPC dist runnable under node ESM (deploy crashloop)

flake.nix only rewrote @/ aliases but left extensionless relative imports
(./router) in compiled dist/. node dist/index.js (how prod runs) cannot
resolve extensionless ESM specifiers -> ERR_MODULE_NOT_FOUND -> backend
crashlooped (444 restarts, port 4001 dead). Extract the fixer into a shared
scripts/fix-imports.mjs that appends .js to extensionless relative imports and
rewrites @/ aliases, and wire it into backend + discord-gateway build phases.

Verified: fresh tsc + fixer -> node dist/index.js boots; oRPC over /trpc
serves both HTTP POST and WebSocket (config/dashboard/voice/moderation/
media/chatbot/analysis) end-to-end against Postgres + Redis. next build
passes with the oRPC client + partysocket.

services/backend/src/http/server.ts

@@ -2,7 +2,7 @@ import { createServer, type Server } from "node:http";
 import { createChildLogger } from "@/shared/logger/index";
 import { config } from "../shared/config/index.js";
 import { initializeDatabase } from "../shared/database/index.js";
-import { createTRPCWebSocketServer } from "../trpc/ws.js";
+import { createORPCWebSocketServer } from "../orpc/ws.js";
 import { startRedisBridge } from "../ws/redis-bridge.js";
 import { createWebSocketServer } from "../ws/server.js";
 import { createHttpApp } from "./app.js";
@@ -19,7 +19,7 @@ export async function startHttpServer(): Promise<Server> {
 
   // Attach WebSocket servers to the same HTTP server
   createWebSocketServer(server); // /ws — voice PCM + gateway events
-  createTRPCWebSocketServer(server); // /trpc — structured data RPCs
+  createORPCWebSocketServer(server); // /trpc — structured data RPCs
 
   // Start Redis pub/sub bridge to forward discord-gateway events to WS clients
   await startRedisBridge();