fix: align SettingsPage prop and state typings

[RutamBhagat]

Summary

• tighten SettingsPage typings for local transcription provider state and setters
• replace ad-hoc toast function object types with shared ToastProps-derived input type
• narrow local provider selection callback to accepted provider IDs before setting state

Stacked PR Context

This PR depends on fix/typecheck-3 and should be reviewed after that PR.

Depends on #211

Output

npm run typecheck

Found 9 errors in 5 files.

Errors  Files
     4  src/components/TitleBar.tsx:41
     1  src/components/ui/MarkdownRenderer.tsx:12
     1  src/helpers/llamaCppInstaller.ts:8
     1  src/lib/neonAuth.ts:119
     2  src/services/ReasoningService.ts:17