refactor(media): remove volume control from FE & BE

Volume sudah di-set default 0.3 di gateway (suara kecil saat play), dan
user bisa naikin sendiri di Discord (command media:volume) — jadi kontrol
volume lewat dashboard tak perlu. Hapus:
- BE: POST /api/media/volume route, mediaVolumeSchema, setVolume service
- FE: useMediaVolume hook, mediaApi.volume, slider volume di music-player
  + mini-player, field volume/setVolume di MediaPlayerProvider
Pertahankan COMMAND_MEDIA_VOLUME di gateway (masih dipakai command DC)
dan mic volume (terpisah, tetap di voice page).

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

@@ -2,8 +2,8 @@ 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 { mediaQueueSchema, mediaVolumeSchema } from "./media.schema.js";
-import { getStatus, queue, setVolume, skip, stop } from "./media.service.js";
+import { mediaQueueSchema } from "./media.schema.js";
+import { getStatus, queue, skip, stop } from "./media.service.js";
 
 const logger = createChildLogger("media.routes");
 
@@ -55,17 +55,5 @@ export function createMediaRouter(): Router {
     }),
   );
 
-  // POST /api/media/volume
-  router.post(
-    "/media/volume",
-    validateBody(mediaVolumeSchema),
-    asyncHandler(async (req: Request, res: Response) => {
-      const { volume } = req.body as { volume: number };
-      logger.debug({ volume }, "Media volume requested");
-      const state = await setVolume(volume);
-      res.json(state);
-    }),
-  );
-
   return router;
 }

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

@@ -5,9 +5,4 @@ export const mediaQueueSchema = z.object({
   mode: z.enum(["music", "screen"]).default("music"),
 });
 
-export const mediaVolumeSchema = z.object({
-  volume: z.number().min(0).max(1).default(0.3),
-});
-
 export type MediaQueueInput = z.infer<typeof mediaQueueSchema>;
-export type MediaVolumeInput = z.infer<typeof mediaVolumeSchema>;

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

@@ -6,7 +6,6 @@ import {
   COMMAND_MEDIA_QUEUE,
   COMMAND_MEDIA_SKIP,
   COMMAND_MEDIA_STOP,
-  COMMAND_MEDIA_VOLUME,
   MEDIA_STATUS_KEY,
 } from "../../shared/index.js";
 import { publishCommand, readRedisStatus } from "../../shared/redis/index.js";
@@ -149,20 +148,3 @@ export async function stop(): Promise<MediaState> {
     "stop",
   );
 }
-
-/**
- * Set volume via Redis command to discord-gateway.
- */
-export async function setVolume(volume: number): Promise<MediaState> {
-  logger.info({ volume }, "setVolume called");
-  return tryCommandThenFallback(
-    () =>
-      publishCommand<MediaState>(
-        COMMAND_MEDIA_VOLUME,
-        { volume },
-        DEFAULT_COMMAND_TIMEOUT_MS,
-      ),
-    () => readStatusFallback(),
-    "setVolume",
-  );
-}