feat(mobile): add smooth reading animation and scroll inertia

[andyWang1688]

Summary

• Add an opt-in Smooth Reading setting, disabled by default to preserve the current performance-first behavior.
• Re-enable foliate-js animated transitions when the setting is enabled.
• Add scroll-mode finger-release inertia behind a dedicated scroll-inertia renderer attribute.
• Cancel inertia on a new touch, touch cancel, navigation lock, programmatic navigation, mode change, document hide, setting disable, and renderer destroy.
• Regenerate the mobile reader.html bundle.

Validation

• node --check packages/foliate-js/paginator.js
• node --check packages/app-expo/scripts/build-reader.js
• Rebuilt packages/app-expo/assets/reader/reader.html
• Parsed all generated reader scripts successfully.
• Browser-level local touch fixture: with inertia enabled, a fast drag continued from 293 to 1240 after release; after disabling the attribute, position remained unchanged after release.

Addresses #581

[codedogQBY]

Verified on a real device. Smooth reading animation and scroll inertia both work as expected. Thanks!