## Summary
Removes duplicate "Download Fonts" menu entry and adds complete
navigation support to the font download activity.
## Problem
"Download Fonts" was appearing in **both** Reader settings and System
settings, creating a confusing duplicate menu entry.
## Changes
### 1. Remove Duplicate Menu Entry
- Removed `STR_DOWNLOAD_FONTS` from `systemSettings` in
`SettingsActivity.cpp`
- "Download Fonts" now only appears in **Reader settings**, positioned
right after the font family setting
- Rationale: Font settings logically belong together in the Reader
category
### 2. Navigation Improvements
- **Single-item navigation**: Replaced manual bounds checking with
`ButtonNavigator::nextIndex()` and `previousIndex()` methods
- Navigation now wraps from last item to first (and vice versa)
- **Page navigation**: Added continuous navigation handlers
- Long-pressing up/down buttons now navigates by page
- Uses `UITheme::getNumberOfItemsPerPage()` for consistent behavior
## Files Changed
- `src/activities/settings/SettingsActivity.cpp`: Removed duplicate
entry
- `src/activities/settings/FontDownloadActivity.cpp`: Navigation
improvements
## Testing
- Build: ✅ Compiled successfully
- Device testing: Recommended before merge
zgredex
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