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/media/index.ts

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

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

@@ -1,71 +0,0 @@
-import type { Request, Response, Router } from "express";
-import express from "express";
-import { createChildLogger } from "@/shared/logger/index";
-import { asyncHandler, validateBody } from "../../shared/middlewares/index.js";
-import { mediaLoopSchema, mediaQueueSchema } from "./media.schema.js";
-import { getStatus, queue, setLoop, skip, stop } from "./media.service.js";
-
-const logger = createChildLogger("media.routes");
-
-export function createMediaRouter(): Router {
-  const router = express.Router();
-
-  // GET /api/media/status
-  router.get(
-    "/media/status",
-    asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media status requested");
-      const status = await getStatus();
-      res.json(status);
-    }),
-  );
-
-  // POST /api/media/queue
-  router.post(
-    "/media/queue",
-    validateBody(mediaQueueSchema),
-    asyncHandler(async (req: Request, res: Response) => {
-      const { source, mode } = req.body as {
-        source: string;
-        mode: "music" | "screen";
-      };
-      logger.debug({ source, mode }, "Media queue requested");
-      const state = await queue(source, mode);
-      res.json(state);
-    }),
-  );
-
-  // POST /api/media/skip
-  router.post(
-    "/media/skip",
-    asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media skip requested");
-      const state = await skip();
-      res.json(state);
-    }),
-  );
-
-  // POST /api/media/stop
-  router.post(
-    "/media/stop",
-    asyncHandler(async (_req: Request, res: Response) => {
-      logger.debug("Media stop requested");
-      const state = await stop();
-      res.json(state);
-    }),
-  );
-
-  // POST /api/media/loop
-  router.post(
-    "/media/loop",
-    validateBody(mediaLoopSchema),
-    asyncHandler(async (req: Request, res: Response) => {
-      const { loop } = req.body as { loop: boolean };
-      logger.debug({ loop }, "Media loop requested");
-      const state = await setLoop(loop);
-      res.json(state);
-    }),
-  );
-
-  return router;
-}