- The `/system` FAT volume is removed. Its files are embedded in the firmware as generated C arrays.
- Default-size fonts are generated at build time and used from flash.
- The LVGL task and the Launcher run on PSRAM-preferred stacks. A new kernel `file_ops` API takes the file work off those threads.
- `MainDispatcher` is reimplemented as an on-demand task.
- More long-lived state is allocated with the PSRAM-preferring helpers.
- Other fixes and improvements
**Fonts**
Dynamically load text and icon fonts when the device boots.
Font bitdepth depends on whether the device is an ESP32 one and whether it has external RAM available.
When no external RAM is available on ESP32, only small and medium font variants are generated; large font variants refer to the medium size ones.
Implemented Appearance settings app for changing font and font size.
**Other changes**
- Added keyboard shortcuts to delete or rename files in directory views.
- Improved app-grid tile sizing to provide more room for labels.
- Reduced the default LED strip brightness.
