fix: remove decimal places from progress % (#507)

## Summary

Addresses
https://github.com/crosspoint-reader/crosspoint-reader/issues/504

- Reverts book progress % to showing as an integer instead of with a
decimal place
- This was changed to 1 decimal point of precision in
https://github.com/crosspoint-reader/crosspoint-reader/pull/232 from
what I can tell
- As this wasn't the primary intention of that PR, I'm assuming it was
left in accidentally

IMO having a decimal place of precision is too much for something as
vague as book completion percent. This de-clutters the status bar and
prevents extra updates as you change pages.

---

### AI Usage

YES

src/activities/reader/EpubReaderActivity.cpp

@@ -448,7 +448,7 @@ void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const in
 
     // Right aligned text for progress counter
     char progressStr[32];
-    snprintf(progressStr, sizeof(progressStr), "%d/%d  %.1f%%", section->currentPage + 1, section->pageCount,
+    snprintf(progressStr, sizeof(progressStr), "%d/%d  %.0f%%", section->currentPage + 1, section->pageCount,
              bookProgress);
     const std::string progress = progressStr;
     progressTextWidth = renderer.getTextWidth(SMALL_FONT_ID, progress.c_str());