chore: enhance Dockerfiles and package.json for improved build process

- Added ENV npm_config_ignore_scripts=true to frontend and backend Dockerfiles to skip scripts during npm install, optimizing build times.
- Introduced a postinstall script in package.json to ensure the build process for @mmapp/contracts runs after installation.

packages/contracts/package.json

@@ -7,8 +7,7 @@
     "dist"
   ],
   "scripts": {
-    "build": "tsc -p tsconfig.json",
-    "prepare": "npm run build"
+    "build": "tsc -p tsconfig.json"
   },
   "exports": {
     ".": {