feat: allow removing book from recent list (#2045)

## Summary

Add ability to long press 'confirm' on a book in the recent books list
to be prompted to remove it from the list.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? *Yes, Claude*

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src/activities/home/RecentBooksActivity.h

@@ -15,12 +15,19 @@ class RecentBooksActivity final : public Activity {
 
   size_t selectorIndex = 0;
 
+  // Set when a long-press has fired; input is swallowed until Confirm is released
+  // again so the release doesn't also open the book.
+  bool longPressFired = false;
+
   // Recent tab state
   std::vector<RecentBook> recentBooks;
 
   // Data loading
   void loadRecentBooks();
 
+  // Show an OK/Cancel prompt to remove the given book from the Recent Books list.
+  void promptRemoveBook(const std::string& path, const std::string& title);
+
  public:
   explicit RecentBooksActivity(GfxRenderer& renderer, MappedInputManager& mappedInput)
       : Activity("RecentBooks", renderer, mappedInput) {}