Update the reader pin for seamless EPUB turns and consistent page counts #100

Pin the client to reader commit 865e94adffe957042cd2a6107173bd05a78a3e87 from PapyrusReader/reader#10 so normal Git-resolved builds receive the EPUB pagination, boundary-animation, and page-count fixes.

Acceptance:

• Update app/pubspec.yaml and both Git references in app/pubspec.lock.
• Resolve and test the Git dependency without a local path override.
• Preserve the existing local development override and unrelated changes.

Requirements: FR-3_1 and FR-3_2.

Dependency: PapyrusReader/reader#10. Related task: PapyrusReader/reader#9. Merge the reader PR before the companion client PR.