How can you fix GRUB boot text being too small to read on a 4K monitor in Bluefin (an immutable Linux system)?

Since Bluefin is an immutable system, you cannot edit GRUB config the traditional way. Instead, modify /etc/default/grub (which is mutable and survives updates) as follows:

Edit /etc/default/grub and add or modify these lines:
```
GRUB_GFXMODE=1920x1080x32
GRUB_GFXPAYLOAD_LINUX=keep
```
This forces GRUB to render at 1080p instead of native 4K, making the text much more readable.
Regenerate the GRUB config:
```
sudo grub2-mkconfig -o /boot/efi/EFI/fedora/grub.cfg
```
Verify the exact path with ls /boot/efi/EFI/ first.
Reboot to see the change.

Important notes:

Changes in /etc survive system updates via OSTree's 3-way merge, so this is safe and persistent.
Do not edit anything under /usr — it is read-only and will be overwritten on the next image update.
Bluefin also has ujust configure-grub for toggling GRUB menu visibility, though it does not directly address resolution.
If there are also HiDPI issues on the desktop itself, Bluefin's GNOME setup includes experimental scaling features like scale-monitor-framebuffer and xwayland-native-scaling.