feat: default to client-side ASR

Summary

Change the default ASR mode from Backend ASR to Client-Side ASR.

Changes Made

• Updated the default ASR state to use Client-Side ASR on application load.
• Kept the Backend ASR toggle visible and fully functional.
• Preserved existing backend transcription behavior when the toggle is enabled.
• Preserved client-side transcription behavior when the toggle is disabled.
• Ensured new sessions and page refreshes start with Client-Side ASR selected by default.

Testing

• Verified Client-Side ASR is selected by default on application load.
• Verified Backend ASR can be enabled through the existing toggle.
• Verified transcription switches correctly between client-side and backend modes.
• Verified page refreshes continue to default to Client-Side ASR.
• Ran test suite successfully.

Files Changed

• src/components/DictationEditor.tsx

Expected Behavior

Backend Toggle	ASR Mode
OFF (default)	Client-Side ASR
ON	Backend ASR

Checklist

• Default ASR mode changed to Client-Side ASR
• Backend toggle remains functional
• Existing backend transcription flow preserved
• Existing client-side transcription flow preserved
• Tests passing

closses #50 (closed)