add settings for behavior when browser keymaps conflict with system or web app keymaps

[chenxin-yan]

Currently, if there are keymap conflicts, the browser prioritizes local keymaps over the keymap you set for it. It would be helpful if users could configure this behavior. This way, the browser could hijack global keymaps, or when a user uses a specific keymap, it would trigger the browser's keymap. If the user activates that keymap twice, it would then use the keymap for the web app, similar to how Arc handles it.

[chenxin-yan]

I am on macOS, and another case where I encountered this issue is when I press Ctrl+f (I set it to switch to a workspace) while the cursor is in a text field, it will move the cursor instead of going to the workspace I set. The reason is that macos has default shortcuts for text-editing and it might conflict with zen browser keymap.