Implement refresh rate toggle/override

[Stafil0]

Closes #54

• Added new refresh rate settings in the mod menu.
• Added overlay controls and an overlay toggle hotkey.
• Added in-game notifications and an overlay with refresh rate information.
• Implemented a flexible overlay with a modular structure.
• Refactored the ModEvent notification system.
• Added deploy flow docs using -p:DeployOutputDir so one command can build and copy mod DLLs to game plugins folder.
• Updated related menus, configs, and the README.

This was slightly out of scope, but I refactored the notification system. It’s mainly a naming refactor, so if you don’t like it, I can revert these changes.

Regarding the refresh rate: we agreed with Panzer to keep the option to set any refresh rate value for testing purposes, but to add notification + permanent overlay that shows the current refresh rate during a run. If it exceeds the 540 Hz threshold, the overlay will indicate that the run is invalid.

And I refactored the FPS toggles and added more precise controls so anyone can select the most comfortable FPS for the skip.