app-backend: remove support for old backend system

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/app-backend/package.json

@@ -26,16 +26,12 @@
   "license": "Apache-2.0",
   "exports": {
     ".": "./src/index.ts",
-    "./alpha": "./src/alpha.ts",
     "./package.json": "./package.json"
   },
   "main": "src/index.ts",
   "types": "src/index.ts",
   "typesVersions": {
     "*": {
-      "alpha": [
-        "src/alpha.ts"
-      ],
       "package.json": [
         "package.json"
       ]
@@ -64,7 +60,6 @@
     "@backstage/plugin-app-node": "workspace:^",
     "@backstage/plugin-auth-node": "workspace:^",
     "@backstage/types": "workspace:^",
-    "@types/express": "^4.17.6",
     "express": "^4.17.1",
     "express-promise-router": "^4.1.0",
     "fs-extra": "^11.2.0",
@@ -81,6 +76,7 @@
     "@backstage/backend-test-utils": "workspace:^",
     "@backstage/cli": "workspace:^",
     "@backstage/types": "workspace:^",
+    "@types/express": "^4.17.6",
     "@types/supertest": "^2.0.8",
     "supertest": "^7.0.0"
   },