mod: Phase 2b - adapt HomeActivity, EpubReaderMenuActivity, EpubReaderActivity

HomeActivity: Add mod features on top of upstream ActivityManager pattern:
- Multi-server OPDS support (OpdsServerStore instead of single URL)
- Long-press recent book for BookManageMenuActivity
- Long-press Browse Files to open archive folder
- Placeholder cover generation for books without covers
- startActivityForResult pattern for manage menu

EpubReaderMenuActivity: Replace upstream menu items with mod menu:
- Add/Remove Bookmark, Lookup Word, Go to Bookmark, Lookup History
- Table of Contents, Toggle Orientation, Toggle Font Size
- Close Book, Delete Dictionary Cache
- Pass isBookmarked and currentFontSize to constructor
- Show current orientation/font size value inline

EpubReaderActivity: Add mod action handlers:
- Bookmark add/remove via BookmarkStore
- Go to Bookmark via EpubReaderBookmarkSelectionActivity
- Dictionary word lookup via DictionaryWordSelectActivity
- Lookup history via LookedUpWordsActivity
- Delete dictionary cache
- Font size toggle with section re-layout
- Close Book action

ActivityResult: Add fontSize field to MenuResult
Made-with: Cursor

src/activities/reader/EpubReaderMenuActivity.h

@@ -21,12 +21,24 @@ class EpubReaderMenuActivity final : public Activity {
     DISPLAY_QR,
     GO_HOME,
     SYNC,
-    DELETE_CACHE
+    DELETE_CACHE,
+    // Mod-specific actions
+    ADD_BOOKMARK,
+    REMOVE_BOOKMARK,
+    LOOKUP_WORD,
+    LOOKUP_HISTORY,
+    GO_TO_BOOKMARK,
+    TABLE_OF_CONTENTS,
+    TOGGLE_ORIENTATION,
+    TOGGLE_FONT_SIZE,
+    CLOSE_BOOK,
+    DELETE_DICT_CACHE
   };
 
   explicit EpubReaderMenuActivity(GfxRenderer& renderer, MappedInputManager& mappedInput, const std::string& title,
                                   const int currentPage, const int totalPages, const int bookProgressPercent,
-                                  const uint8_t currentOrientation, const bool hasFootnotes);
+                                  const uint8_t currentOrientation, const bool hasFootnotes,
+                                  bool isBookmarked = false, uint8_t currentFontSize = 0);
 
   void onEnter() override;
   void onExit() override;
@@ -39,7 +51,7 @@ class EpubReaderMenuActivity final : public Activity {
     StrId labelId;
   };
 
-  static std::vector<MenuItem> buildMenuItems(bool hasFootnotes);
+  static std::vector<MenuItem> buildMenuItems(bool hasFootnotes, bool isBookmarked);
 
   // Fixed menu layout
   const std::vector<MenuItem> menuItems;
@@ -49,9 +61,11 @@ class EpubReaderMenuActivity final : public Activity {
   ButtonNavigator buttonNavigator;
   std::string title = "Reader Menu";
   uint8_t pendingOrientation = 0;
+  uint8_t pendingFontSize = 0;
   uint8_t selectedPageTurnOption = 0;
   const std::vector<StrId> orientationLabels = {StrId::STR_PORTRAIT, StrId::STR_LANDSCAPE_CW, StrId::STR_INVERTED,
                                                 StrId::STR_LANDSCAPE_CCW};
+  const std::vector<StrId> fontSizeLabels = {StrId::STR_SMALL, StrId::STR_MEDIUM, StrId::STR_LARGE, StrId::STR_X_LARGE};
   const std::vector<const char*> pageTurnLabels = {I18N.get(StrId::STR_STATE_OFF), "1", "3", "6", "12"};
   int currentPage = 0;
   int totalPages = 0;