1.0.67: fix: improve transcription success/failure status reporting

• Add gpt-4o-transcribe and gpt-4o-mini-transcribe models to OpenAI provider
• Implement dynamic audio format selection (MP4/M4A preferred over WebM)
• Pass actual recording MIME type from frontend to backend for proper file extension
• Fix audio format mismatch that caused "Audio file might be corrupted" errors
• Fix misleading "transcription failed" error when transcription succeeds but text insertion fails
• Remove unreliable "Text insertion completed successfully" console log
• Simplify status logic to avoid false claims about text insertion success