createPhotoInExternalDir
Creates a file for photo capture in the external pictures directory.
The file is created in the app-specific external pictures directory:
Primary:
{externalFilesDir}/Pictures/STREAM_IMG_{timestamp}.jpgFallback:
{cacheDir}/stream_cache/STREAM_IMG_{timestamp}.jpg(if external storage unavailable)
The file name includes a timestamp to ensure uniqueness.
Return
Result.Success with the created File, or Result.Failure with an error
Parameters
context
Android context for accessing storage directories