fix: postinstall 中覆盖 env 文件,防止 emb 内部 npm install 后丢失

emb 内部会执行 npm install,可能重置 .env 文件。
将 env 覆盖逻辑放入 postinstall,在 CI=true 时自动
将 .env.test 复制到 .env 和 .env.production。
1 job for main in 1 minute and 34 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
failed #127845
studio-2023
ci-build

00:01:34

 
Name Stage Failure
failed
ci-build Build
$ cd packages/app
$ export APP_DIR=$(pwd)
$ npm install --legacy-peer-deps
npm ERR! code EOVERRIDE
npm ERR! Override for expo-modules-core@^2.2.1 conflicts with direct dependency

npm ERR! A complete log of this run can be found in: /Users/mac-2023/.npm/_logs/2026-03-10T07_25_28_365Z-debug-0.log
Cleaning up project directory and file based variables
ERROR: Job failed: exit status 1