🐛 fix(settings): fixed bug preventing custom headers from being saved

The issue was that when users added or modified custom headers, the changes were only stored in the local component state but never propagated to the main configuration object that gets saved.

The fix adds a `useEffect` hook that updates the main configuration whenever the custom headers change, ensuring they're properly saved when the user clicks the "Save" button.

Now users can successfully add custom headers to their OpenAI Compatible provider configurations.

Test plan:
- Added a header confirmed it saved
- Added header, discarded changes, confirmed header is gone

Author: hassoncs

.changeset/beige-meals-win.md

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+---
+"roo-cline": patch
+---
+
+Fix Custom Headers are not saved for OpenAI Compatible providers