CPR-vCodex Steroids — Quick Fixes

⚡ Library Performance

🚀 Instant open — incremental scan skips all e-ink refreshes and DFS counting pass. Library opens immediately when no books changed
📊 Dynamic progress bar — ~10 updates total regardless of library size (230 books → every 23, 50 books → every 5)
🔍 Binary search scan — O(log n) file matching via sorted array + std::lower_bound, zero extra RAM vs old hash map
📁 No per-file I/O — file sizes read from directory entries, eliminating hundreds of Storage.open() calls

📑 Proper pagination — collectionBookCount() reads exact count from index, works correctly with 47+ books per collection
🔄 Cover generation — works inside collections just like normal browsing mode
↩️ Back navigation — collection books → collection list → library exit

🔄 First↔last page wrap — lastPage_ properly updated on every wrap-around transition
📄 Page cache refresh — called on all page changes (Up/Down/Left/Right) for correct display
🎯 Selector never empty — clamped to valid positions on incomplete last pages

✅ Library always in sync — incremental LibraryIndex::scan() on every entry detects added/removed/modified books
🛡️ Renders suppressed during scan — no unrelated Activity renders during walkDirs() processing pass
🗑️ index rebuild skipped — buildIndices() only runs when books actually changed (added > 0 || removed > 0)