Add complete Kobo highlight sync system with NickelMenu integration

- Add text cleaning to remove page reference numbers (e.g., "10After" -> "After")
- Implement cleanHighlightText() function with boundary detection
- Add NickelMenu configuration for UI integration
- Create sync wrapper scripts (with and without FBInk notifications)
- Add installation guides for Kobo deployment
- Include pointer/slice explanation examples for learning

Features:
- Extracts highlights from Kobo SQLite database
- Cleans page references from academic texts
- Computes SHA-256 hashes for deduplication
- POSTs JSON to Flask API endpoint
- Supports ARM static linking for Kobo hardware
- Optional FBInk notifications for user feedback

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

nickel_menu_config

@@ -0,0 +1,9 @@
+# NickelMenu configuration for kb_exfiltrator
+# Copy this to: /mnt/onboard/.adds/nm/kb_exfiltrator
+# Or append to existing NickelMenu config
+
+menu_item :main    :Sync Highlights    :cmd_spawn         :quiet :exec /usr/local/bin/sync_highlights.sh
+menu_item :reader  :Sync Highlights    :cmd_spawn         :quiet :exec /usr/local/bin/sync_highlights.sh
+
+# Alternative: Show output in a dialog
+# menu_item :main    :Sync Highlights    :cmd_output        :500:/usr/local/bin/sync_highlights.sh