Add RDEPUBBackgroundTrace.log at key decision points in the
reconciliation pipeline to trace why pageMap updates get rejected:
1. refreshBookPageMapInPlace — logs when a full pageMap update is enqueued
2. evaluateTakeover — logs when keepCurrentWindow is returned due to:
- jumpSession coverage ratio < 0.8
- adjacent coverage missing (hasPrev/hasNext)
- renderSignature mismatch
3. evaluateFullPageMapTakeover — logs when keepCurrentWindow is returned due to:
- currentSpineIndex not in candidate chapters
- adjacent coverage missing
4. commitPendingPageMapUpdate — logs when keepCurrentWindow decision is
applied and pending update is removed from queue
Also fix unused variable warning for currentPageNumber in extendPartial case.
Co-Authored-By: Claude <noreply@anthropic.com>
b8aa10c535