feat: unify navigation handling with system-wide continuous navigation (#600)

This PR unifies navigation handling & adds system-wide support for
continuous navigation.

## Summary
Holding down a navigation button now continuously advances through items
until the button is released. This removes the need for repeated
press-and-release actions and makes navigation faster and smoother,
especially in long menus or documents.

When page-based navigation is available, it will navigate through pages.
If not, it will progress through menu items or similar list-based UI
elements.

Additionally, this PR fixes inconsistencies in wrap-around behavior and
navigation index calculations.

Places where the navigation system was updated:
- Home Page
- Settings Pages
- My Library Page
- WiFi Selection Page
- OPDS Browser Page
- Keyboard
- File Transfer Page
- XTC Chapter Selector Page
- EPUB Chapter Selector Page

I’ve tested this on the device as much as possible and tried to match
the existing behavior. Please let me know if I missed anything. Thanks 🙏


![crosspoint](https://github.com/user-attachments/assets/6a3c7482-f45e-4a77-b156-721bb3b679e6)

---

Following the request from @osteotek and @daveallie for system-wide
support, the old PR (#379) has been closed in favor of this
consolidated, system-wide implementation.

---

### AI Usage

Did you use AI tools to help write this code? _**PARTIALLY**_

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

src/activities/home/RecentBooksActivity.cpp

@@ -12,7 +12,6 @@
 #include "util/StringUtils.h"
 
 namespace {
-constexpr int SKIP_PAGE_MS = 700;
 constexpr unsigned long GO_HOME_MS = 1000;
 }  // namespace
 
@@ -70,13 +69,6 @@ void RecentBooksActivity::onExit() {
 }
 
 void RecentBooksActivity::loop() {
-  const bool upReleased = mappedInput.wasReleased(MappedInputManager::Button::Left) ||
-                          mappedInput.wasReleased(MappedInputManager::Button::Up);
-  ;
-  const bool downReleased = mappedInput.wasReleased(MappedInputManager::Button::Right) ||
-                            mappedInput.wasReleased(MappedInputManager::Button::Down);
-
-  const bool skipPage = mappedInput.getHeldTime() > SKIP_PAGE_MS;
   const int pageItems = UITheme::getInstance().getNumberOfItemsPerPage(renderer, true, false, true, true);
 
   if (mappedInput.wasReleased(MappedInputManager::Button::Confirm)) {
@@ -92,21 +84,26 @@ void RecentBooksActivity::loop() {
   }
 
   int listSize = static_cast<int>(recentBooks.size());
-  if (upReleased) {
-    if (skipPage) {
-      selectorIndex = std::max(static_cast<int>((selectorIndex / pageItems - 1) * pageItems), 0);
-    } else {
-      selectorIndex = (selectorIndex + listSize - 1) % listSize;
-    }
+
+  buttonNavigator.onNextRelease([this, listSize] {
+    selectorIndex = ButtonNavigator::nextIndex(static_cast<int>(selectorIndex), listSize);
     updateRequired = true;
-  } else if (downReleased) {
-    if (skipPage) {
-      selectorIndex = std::min(static_cast<int>((selectorIndex / pageItems + 1) * pageItems), listSize - 1);
-    } else {
-      selectorIndex = (selectorIndex + 1) % listSize;
-    }
+  });
+
+  buttonNavigator.onPreviousRelease([this, listSize] {
+    selectorIndex = ButtonNavigator::previousIndex(static_cast<int>(selectorIndex), listSize);
     updateRequired = true;
-  }
+  });
+
+  buttonNavigator.onNextContinuous([this, listSize, pageItems] {
+    selectorIndex = ButtonNavigator::nextPageIndex(static_cast<int>(selectorIndex), listSize, pageItems);
+    updateRequired = true;
+  });
+
+  buttonNavigator.onPreviousContinuous([this, listSize, pageItems] {
+    selectorIndex = ButtonNavigator::previousPageIndex(static_cast<int>(selectorIndex), listSize, pageItems);
+    updateRequired = true;
+  });
 }
 
 void RecentBooksActivity::displayTaskLoop() {