chore(backend): move @types/* to devDependencies (#813)

The seven @types/* packages contain only TypeScript declaration files,
which are erased at compile time and have no runtime use. Listing them
under dependencies kept them installed in the production image for no
benefit; they belong under devDependencies so `npm ci --omit=dev`
prunes them from the runtime install.

Packages moved: @types/compression, @types/cors, @types/dockerode,
@types/express, @types/http-proxy, @types/semver, @types/ws.

backend/package.json

@@ -22,13 +22,20 @@
     "@eslint/js": "^10.0.1",
     "@types/bcrypt": "^6.0.0",
     "@types/better-sqlite3": "^7.6.13",
+    "@types/compression": "^1.8.1",
     "@types/cookie-parser": "^1.4.10",
+    "@types/cors": "^2.8.19",
+    "@types/dockerode": "^4.0.1",
+    "@types/express": "^5.0.6",
+    "@types/http-proxy": "^1.17.17",
     "@types/http-proxy-middleware": "^1.0.0",
     "@types/jsonwebtoken": "^9.0.10",
     "@types/multer": "^2.1.0",
     "@types/node": "^25.3.0",
+    "@types/semver": "^7.7.1",
     "@types/supertest": "^7.2.0",
     "@types/tar-stream": "^3.1.4",
+    "@types/ws": "^8.18.1",
     "@types/yaml": "^1.9.6",
     "eslint": "^10.1.0",
     "nodemon": "^3.1.13",
@@ -41,13 +48,6 @@
   "dependencies": {
     "@aws-sdk/client-ecr": "^3.1019.0",
     "@aws-sdk/client-s3": "^3.1037.0",
-    "@types/compression": "^1.8.1",
-    "@types/cors": "^2.8.19",
-    "@types/dockerode": "^4.0.1",
-    "@types/express": "^5.0.6",
-    "@types/http-proxy": "^1.17.17",
-    "@types/semver": "^7.7.1",
-    "@types/ws": "^8.18.1",
     "axios": "^1.15.0",
     "bcrypt": "^6.0.0",
     "better-sqlite3": "^12.6.2",