Fixes #5462

Problem

CLI status bar always showed the initial provider/model even after switching to a different provider.

Solution

• Extract "apiConfiguration" from extension state messages in "useMessageHandlers.ts"
• Derive current provider/model from store (with fallback to initial props) in "App.tsx"

Changes

• "apps/cli/src/ui/App.tsx": Use store values for Header component
• "apps/cli/src/ui/hooks/useMessageHandlers.ts": Extract and update apiConfiguration from state

Testing

• Build passes ✅
• Type checks pass ✅
• Lint passes ✅
• Unit tests pass ✅