refactor(backend): split stream routes into focused modules

Backend/routes/streams/shared.ts

@@ -0,0 +1,29 @@
+import type { Request, Response } from 'express';
+import { and, eq } from 'drizzle-orm';
+
+import { db } from '../../db/client';
+import { streamSessions } from '../../db/schema';
+import { mediaMode, streamRecordingEnabled } from '../../media/config';
+
+export const ensureStreamDeviceAuth = (req: Request, res: Response) => {
+  const deviceAuth = req.deviceAuth;
+
+  if (!deviceAuth) {
+    res.status(401).json({ message: 'Unauthorized' });
+    return null;
+  }
+
+  return deviceAuth;
+};
+
+export const getOwnedStreamSession = async (streamSessionId: string, ownerUserId: string) =>
+  await db.query.streamSessions.findFirst({
+    where: and(eq(streamSessions.id, streamSessionId), eq(streamSessions.ownerUserId, ownerUserId)),
+  });
+
+export const isStreamParticipant = (
+  session: { requesterDeviceId: string; cameraDeviceId: string },
+  deviceId: string,
+): boolean => session.requesterDeviceId === deviceId || session.cameraDeviceId === deviceId;
+
+export const shouldCreateRecordingPlaceholder = (): boolean => mediaMode === 'legacy' || streamRecordingEnabled;