Few improvements

[mykeehu]

I have a few comments about the app:

• For cortex-based builds, I can't use CPU mode to load because the app quits
• I can't stop the generation, a stop button would be nice
• When loading Lora, I specify the folder, but there is no file selection window, it simply loads the contents of the folder. It can also load an entire model, not just Lora.
• It would be a good idea to disable screen turning off in the settings or allow it to run in the background, because the phone will put the app to sleep as soon as the screen turns off.
• Whether I use the Cortex 520 or 720 version with OpenCL, the generation speed does not change. I use it on Honor Magic 6 Pro.