On ESP32-C3 with USB CDC, Serial.printf() blocks indefinitely when USB
is not connected. This caused device freezes when booted without USB.
Solution: Call Serial.setTxTimeoutMs(0) after Serial.begin() to make
all Serial output non-blocking.
Also added if (Serial) guards to high-traffic logging paths in
EpubReaderActivity as belt-and-suspenders protection.
Includes documentation of the debugging process and Serial call inventory.
Also applies clang-format to fix pre-existing formatting issues.
- Add pill badge system for displaying file type and suffix tags
- Add "Remove from Recents" option to remove individual books
- Add "Clear All Recents" option to clear entire recents list
- Add clearThumbExistsCache() for cache invalidation
- Create BadgeConfig.h for customizable badge mappings
- Add extractBookTags() utility for parsing filename badges
- Add drawPillBadge() component for rendering badges
Adds full support for book lists managed by the Companion App:
- New /list API endpoints (GET/POST) for uploading, retrieving, and deleting lists
- BookListStore for binary serialization of lists to /.lists/ directory
- ListViewActivity for viewing list contents with book thumbnails
- Reading Lists tab in My Library with pin/unpin and delete actions
- Pinnable list shortcut on home screen (split button layout)
- Automatic cleanup of pinned status when lists are deleted
