fix(server): require embedded-postgres for embedded DB mode

server/package.json

@@ -41,6 +41,7 @@
     "detect-port": "^2.1.0",
     "dotenv": "^17.0.1",
     "drizzle-orm": "^0.38.4",
+    "embedded-postgres": "^18.1.0-beta.16",
     "express": "^5.1.0",
     "multer": "^2.0.2",
     "open": "^11.0.0",
@@ -50,9 +51,6 @@
     "ws": "^8.19.0",
     "zod": "^3.24.2"
   },
-  "optionalDependencies": {
-    "embedded-postgres": "^18.1.0-beta.16"
-  },
   "devDependencies": {
     "@types/express": "^5.0.0",
     "@types/express-serve-static-core": "^5.0.0",