Remove all RDEPUBBackgroundTrace.log and bare print diagnostic calls

Keep only the evaluateFullPageMapTakeover: fullReplace diagnostic log
in RDEPUBPageMapReconciliationCoordinator.swift for future debugging.

Simplified RDEPUBBackgroundTrace to just the log method (removed measure
and debug gating). Removed all [EPUB][...], [ReadViewDemo], and
[EPUB][Pagination] print statements across the project.

Also includes earlier bug fixes:
- Fix stale currentPageNumber in extendPartial commit
- Fix pageCurl rebindVisiblePage during transition
- Fix keepCurrentWindow not removing pending update from queue
- Fix right-aligned text (巫鸿 bug) via avoidPageBreakInside,
  tail merger, and continuation paragraph normalization
- Add text-indent reset for aligned blocks in CSS compatibility layer

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

Sources/RDReaderView/EPUBUI/ReaderController/RDEPUBNavigationStateMachine.swift

@@ -67,10 +67,9 @@ final class RDEPUBNavigationStateMachine {
             isValid = false
         }
         if !isValid {
-            RDEPUBBackgroundTrace.log(
-                "NavigationStateMachine",
-                "WARNING: unexpected transition \(oldState) → \(newState)"
-            )
+            #if DEBUG
+            assertionFailure("Unexpected navigation state transition: \(oldState) → \(newState)")
+            #endif
         }
     }
     #endif