mod: adapt mod activities to #774 render() pattern

Migrate 5 mod Activity subclasses from old polling-based
display task pattern to the upstream render() super-class
pattern with freeRTOS notification:

- EpubReaderBookmarkSelectionActivity
- DictionaryWordSelectActivity
- DictionarySuggestionsActivity
- DictionaryDefinitionActivity
- LookedUpWordsActivity

Changes: remove own TaskHandle/SemaphoreHandle/updateRequired,
use requestUpdate() + render(RenderLock&&) override, fix
potential deadlocks around enterNewActivity() calls.

Also fix stale conflict marker in EpubReaderMenuActivity.h.

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

src/activities/reader/DictionaryWordSelectActivity.h

@@ -1,8 +1,5 @@
 #pragma once
 #include <Epub/Page.h>
-#include <freertos/FreeRTOS.h>
-#include <freertos/semphr.h>
-#include <freertos/task.h>
 
 #include <functional>
 #include <memory>
@@ -31,6 +28,7 @@ class DictionaryWordSelectActivity final : public ActivityWithSubactivity {
   void onEnter() override;
   void onExit() override;
   void loop() override;
+  void render(Activity::RenderLock&&) override;
 
  private:
   struct WordInfo {
@@ -64,19 +62,12 @@ class DictionaryWordSelectActivity final : public ActivityWithSubactivity {
   std::vector<Row> rows;
   int currentRow = 0;
   int currentWordInRow = 0;
-  bool updateRequired = false;
   bool pendingBackFromDef = false;
   bool pendingExitToReader = false;
 
-  TaskHandle_t displayTaskHandle = nullptr;
-  SemaphoreHandle_t renderingMutex = nullptr;
-
   bool isLandscape() const;
   bool isInverted() const;
   void extractWords();
   void mergeHyphenatedWords();
-  void renderScreen();
   void drawHints();
-  static void taskTrampoline(void* param);
-  [[noreturn]] void displayTaskLoop();
 };