#369 fix(desktop): inject NODE_ENV into main and preload builds

Summary

• Fix production builds using .superset-dev instead of .superset
• Inject NODE_ENV into main and preload process builds via Vite define
• Defaults to "production" when not set (matches expected behavior for packaged apps)

Root cause

The renderer build had NODE_ENV: "production" injected via injectProcessEnvPlugin, but main/preload builds relied on process.env.NODE_ENV at runtime, which isn't set in packaged Electron apps.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Chores
  • Updated build configuration to ensure consistent environment variable handling across build pipelines.

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