Allow switching to player mode on demand

[CreeperPookie]

Is your feature request related to a problem? Please describe.
Although I absolutely love player mode (especially the drop mode!) one thing that would be very helpful is to allow switching between editor and player more freely. Something I've used a lot in my songs is to open my songs in player mode to get a better idea of note positions and especially pitch transitions; however, this means I effectively have to restart NBS to switch between the two modes, which can be an issue, especially for a lot of minor edits.

Describe the enhancement you'd like
The best option would be to add an entry to one of the top dropdown menus (like Edit or Settings) that would enable/disable player mode without restarting NBS. Another option could be adding a new button to the player/editor control bar, though on smaller screens (or even windows) it could become harder to access.

Additional context
While I do realize player mode is supposed to be - in a sense - "NBS Lite" (in that player mode provides a simpler UI and features to only listen to songs) I still think there are a lot of instances when switching between each mode can be very useful, especially for trying to see your song in a different context and make a quick edit to it.
This would mean needing to redraw the screen when a mode change was requested though, which could be tricky; however (although I don't know the GameMaker language very well yet) the player button on the greeting screen (https://github.com/OpenNBS/NoteBlockStudio/blob/main/scripts/draw_window_greeting/draw_window_greeting.gml#L305) mostly seems to set a variable (effectively a boolean) value to 1 and redraw the screen (maybe redrawing the screen is a non-issue!)

[OctoFlareDev]

Hello! The player mode is designed to be non-quittable on demand due to the logics of people might not want to accidentally make an edit to a song file and the incoming multiple tabs opening feature, and player mode can open only one song. Although with that being said, I think it is good to add a button to launch a player mode instance in nbs instead.

[Bentroen]

Additionally, the upcoming v4.0 may rely on songs being read-only to do some performance optimizations, allowing the app to run faster by not loading the song editing features. These are technical challenges we'd have to overcome before letting one freely switch between the different modes.

[CreeperPookie]

yeah I understand that, I've definitely used my share of "read-only-mode" apps for just that reason before (including NBS too) and I definitely can see the appeal of disabling editing; also it's not just v4.0, even in the current version I have seen songs play a little faster when in player mode, most noticible for me when playing a looping song, which definitely starts sooner than in editor mode (not enough to be completely off tempo or anything at all, but still definitely noticible)
either way I just wanted to mention how hotswapping between player and editor could be useful too :D