fix: switch to Railpack with proper pnpm and yarn configuration

nixpacks.toml

@@ -1,11 +0,0 @@
-[phases.setup]
-nixPkgs = ["nodejs_20", "yarn"]
-
-[phases.install]
-cmds = ["pnpm i --frozen-lockfile"]
-
-[phases.build]
-cmds = ["./scripts/railway-build.sh"]
-
-[start]
-cmd = "pnpm run start"

railpack-plan.json

@@ -0,0 +1,7 @@
+{
+  "packages": {
+    "node": "20",
+    "pnpm": "9",
+    "yarn": "1"
+  }
+}

railway.toml

@@ -1,7 +0,0 @@
-[build]
-builder = "NIXPACKS"
-
-[deploy]
-startCommand = "pnpm run start"
-restartPolicyType = "ON_FAILURE"
-restartPolicyMaxRetries = 10