feat(backend,frontend): migrate data APIs from REST to native tRPC over WebSocket

Replace REST module routers with a single typed tRPC appRouter served over
/trpc (HTTP + WebSocket), and rewire the frontend to call it via
@trpc/client wsLink (browser) and httpLink (RSC data layer). Existing
/api/health + /api/metrics stay as plain Express for infra scraping.

Notable fixes surfaced by the live smoke test:
- Express 5 / path-to-regexp v8 rejects the /trpc/* wildcard route; use a
  prefix middleware that computes opts.path from the URL instead.
- nodeHTTPRequestHandler treats opts.path as the literal procedure path, so
  it is derived per-request from req.url.
- Two ws servers on one http.Server (the /ws voice socket + /trpc) collided
  and returned 400 on upgrade; both now use noServer + a manually routed
  server.on('upgrade') keyed by path.

Verified: BE tsc+biome+40 vitest green; FE tsc+biome green; live
HTTP and WebSocket calls returned real prod data.

Co-Authored-By: Claude Opus 4.5 (1M context) <noreply@anthropic.com>

services/backend/src/modules/chatbot/chatbot.controller.ts

@@ -1,96 +0,0 @@
-import type { Request, Response } from "express";
-import { createChildLogger } from "@/shared/logger/index";
-import { asyncHandler } from "../../shared/middlewares/index.js";
-import { chatbotService } from "./chatbot.service.js";
-
-const logger = createChildLogger("chatbot.controller");
-
-interface AuthenticatedRequest extends Request {
-  userId?: string;
-}
-
-/**
- * Resolve the actor id for a request. Frontend (no-login) sends a per-device
- * UUID via X-User-Id so chat history stays isolated per visitor; a registered
- * auth middleware userId takes precedence when present.
- */
-function resolveUserId(req: Request): string {
-  const authId = (req as AuthenticatedRequest).userId;
-  if (authId) return authId;
-  const header = (req.headers["x-user-id"] as string | undefined)?.trim();
-  return header || "anonymous";
-}
-
-export const handleChatbotChat = asyncHandler(
-  async (req: Request, res: Response) => {
-    const { message, context } = req.body as {
-      message: string;
-      context?: Record<string, unknown>;
-    };
-
-    // Validate required fields
-    if (!message || typeof message !== "string") {
-      return res.status(400).json({
-        error: "INVALID_INPUT",
-        message: "Message is required and must be a string",
-      });
-    }
-
-    // Get user ID from X-User-Id header (no-login device uuid) or auth
-    const userId = resolveUserId(req);
-
-    logger.debug(
-      { userId, messageLength: message.length, context },
-      "Received chatbot chat message",
-    );
-
-    // Process message & generate response
-    const response = await chatbotService.processMessage(
-      message,
-      context,
-      userId,
-    );
-
-    // Save conversation to database
-    await chatbotService.saveConversation({
-      userId,
-      userMessage: message,
-      botResponse: response,
-      context,
-      timestamp: new Date(),
-    });
-
-    logger.info({ userId }, "Chatbot chat processed successfully");
-
-    res.status(200).json({
-      response,
-      timestamp: new Date().toISOString(),
-    });
-  },
-);
-
-export const getChatbotHistory = asyncHandler(
-  async (req: Request, res: Response) => {
-    const userId = resolveUserId(req);
-    const limit = Math.min(parseInt(req.query.limit as string, 10) || 50, 100);
-
-    const history = await chatbotService.getChatHistory(userId, limit);
-
-    res.status(200).json({
-      history,
-      total: history.length,
-    });
-  },
-);
-
-export const clearChatbotHistory = asyncHandler(
-  async (req: Request, res: Response) => {
-    const userId = resolveUserId(req);
-
-    await chatbotService.clearChatHistory(userId);
-
-    res.status(200).json({
-      message: "Chat history cleared successfully",
-    });
-  },
-);

services/backend/src/modules/chatbot/chatbot.routes.ts

@@ -1,18 +0,0 @@
-import express, { type Router } from "express";
-import { validateBody } from "../../shared/middlewares/index.js";
-import {
-  clearChatbotHistory,
-  getChatbotHistory,
-  handleChatbotChat,
-} from "./chatbot.controller.js";
-import { chatRequestSchema } from "./chatbot.schema.js";
-
-export function createChatbotRouter(): Router {
-  const router = express.Router();
-
-  router.post("/chat", validateBody(chatRequestSchema), handleChatbotChat);
-  router.get("/chat/history", getChatbotHistory);
-  router.delete("/chat/history", clearChatbotHistory);
-
-  return router;
-}

services/backend/src/modules/chatbot/index.ts

@@ -1 +0,0 @@
-export { createChatbotRouter } from "./chatbot.routes.js";