bugfix/out-of-sync-data-source

[BrianWhitneyAI]

Description

The purpose of this PR is to resolve #398 and centralize the data source variable in the main process so that the "Data Source" menu always reflects the current state, allows users to change it, and persists those changes across app restarts, refreshes and cache clears.

Changes

• Added an envManager.ts module that loads the persisted environment on startup and updates it (persisting the new value and rebuilding the menu).

• Changed the Data Source menu to be built dynamically (via a function) so that its radio buttons always reflect the current environment.

• Modified the menu click to call updateEnvironment() (which updates state and rebuilds the menu) and send an event. The main process loads the environment before building the menu, and the renderer listens for updates to re‑render the UI.

Testing

1. Open app and select staging
2. Refresh / Reload / Clear Cache
3. Check that correct data source is selected and matches data
4. repeat and iterate for different env / data sources

[BrianWhitneyAI]

Something funky, github doesn't seem to be tracking indent changes. I tried to adhere to 4 space indents but may have missed some.