Add opt-in smart resume for newly available chapters

[PoonHarpoon]

Currently, when you're finished with a chapter and a new update is posted, you click on it and end up loading both the end of the old chapter and, inevitably, the next chapter. This PR adds an opt-in feature called smart resume that, depending on the configurable settings, will automatically skip to the new chapter's first page, making it both smoother and requiring less to load and process overall.

I feel like it could use some more feedback on the behavior, as I just designed it to fix an annoyance that goes hand in hand with the problem the prefetch PR fixes.

Settings appear inline after the reader-mode controls:

• Smart resume defaults to off.
• Completion uses either percentage of pages reached (default 90%) or pages remaining (default one).
• Both thresholds accept exact whole-number entry and retain independent values.
• An optional, default-off update wait has a separate help button explaining latency and cached chapter data.

With waiting off, the first usable chapter list determines the position; later updates cannot trigger a jump.
With waiting on, potentially eligible starts wait for the normal details update without forcing a refresh.
Original history is captured before recovery or startup writes. Recovered history is ineligible. Failed updates
or empty/failed successor loads preserve the saved position; cancellation propagates.

Completion counts the current source page as reached, rather than scroll distance within a long image.
Previous-latest detection uses the saved chapter count and assumes chapters are appended in reading order.
The implementation uses existing preferences, with no database migration or new dependency.

I compiled the APK and tested it on my phone and an emulator; both are working as expected.

[LandWarderer2772]

This looks like an actually useful feature, i have had the same experience.