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>

lib/I18n/I18nKeys.h

@@ -365,6 +365,11 @@ enum class StrId : uint16_t {
   STR_DICT_CACHE_DELETED,
   STR_NO_CACHE_TO_DELETE,
   STR_TABLE_OF_CONTENTS,
+  STR_TOGGLE_ORIENTATION,
+  STR_TOGGLE_FONT_SIZE,
+  STR_OVERRIDE_LETTERBOX_FILL,
+  STR_PREFERRED_PORTRAIT,
+  STR_PREFERRED_LANDSCAPE,
   // Sentinel - must be last
   _COUNT
 };