mod: overhaul reader menu with long-press actions and quick toggles

Consolidate dictionary items: remove "Lookup Word History" and
"Delete Dictionary Cache" from the menu. Long-press on "Lookup Word"
opens history; delete-dict-cache is now a sentinel entry at the bottom
of the history list.

Replace "Reading Orientation" with "Toggle Portrait/Landscape" that
toggles between two configurable preferred orientations (new settings:
Preferred Portrait, Preferred Landscape). Long-press opens a manual
4-option orientation sub-menu.

Add "Toggle Font Size" menu item that cycles through font sizes and
applies on menu exit (with section re-layout).

Rename "Letterbox Fill" to "Override Letterbox Fill" and
"Sync Progress" to "Sync Reading Progress" in reader menu.

All long-press flows use ignoreNextConfirmRelease to prevent the
button release from triggering actions on the subsequent screen.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/activities/reader/LookedUpWordsActivity.h

@@ -10,13 +10,14 @@ class LookedUpWordsActivity final : public ActivityWithSubactivity {
  public:
   explicit LookedUpWordsActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, const std::string& cachePath,
                                  int readerFontId, uint8_t orientation, const std::function<void()>& onBack,
-                                 const std::function<void()>& onDone)
+                                 const std::function<void()>& onDone, bool initialSkipRelease = false)
       : ActivityWithSubactivity("LookedUpWords", renderer, mappedInput),
         cachePath(cachePath),
         readerFontId(readerFontId),
         orientation(orientation),
         onBack(onBack),
-        onDone(onDone) {}
+        onDone(onDone),
+        ignoreNextConfirmRelease(initialSkipRelease) {}
 
   void onEnter() override;
   void onExit() override;
@@ -41,5 +42,9 @@ class LookedUpWordsActivity final : public ActivityWithSubactivity {
   bool ignoreNextConfirmRelease = false;
   int pendingDeleteIndex = 0;
 
+  // Sentinel index: the "Delete Dictionary Cache" entry at the end of the list.
+  // -1 if not present (shouldn't happen when dictionary exists).
+  int deleteDictCacheIndex = -1;
+
   int getPageItems() const;
 };