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.cpp

@@ -14,45 +14,19 @@
 #include "util/Dictionary.h"
 #include "util/LookupHistory.h"
 
-void DictionaryWordSelectActivity::taskTrampoline(void* param) {
-  auto* self = static_cast<DictionaryWordSelectActivity*>(param);
-  self->displayTaskLoop();
-}
-
-void DictionaryWordSelectActivity::displayTaskLoop() {
-  while (true) {
-    if (updateRequired && !subActivity) {
-      updateRequired = false;
-      xSemaphoreTake(renderingMutex, portMAX_DELAY);
-      renderScreen();
-      xSemaphoreGive(renderingMutex);
-    }
-    vTaskDelay(10 / portTICK_PERIOD_MS);
-  }
-}
-
 void DictionaryWordSelectActivity::onEnter() {
   ActivityWithSubactivity::onEnter();
-  renderingMutex = xSemaphoreCreateMutex();
   extractWords();
   mergeHyphenatedWords();
   if (!rows.empty()) {
     currentRow = static_cast<int>(rows.size()) / 3;
     currentWordInRow = 0;
   }
-  updateRequired = true;
-  xTaskCreate(&DictionaryWordSelectActivity::taskTrampoline, "DictWordSelTask", 4096, this, 1, &displayTaskHandle);
+  requestUpdate();
 }
 
 void DictionaryWordSelectActivity::onExit() {
   ActivityWithSubactivity::onExit();
-  xSemaphoreTake(renderingMutex, portMAX_DELAY);
-  if (displayTaskHandle) {
-    vTaskDelete(displayTaskHandle);
-    displayTaskHandle = nullptr;
-  }
-  vSemaphoreDelete(renderingMutex);
-  renderingMutex = nullptr;
 }
 
 bool DictionaryWordSelectActivity::isLandscape() const {
@@ -231,7 +205,7 @@ void DictionaryWordSelectActivity::loop() {
     if (pendingBackFromDef) {
       pendingBackFromDef = false;
       exitActivity();
-      updateRequired = true;
+      requestUpdate();
     }
     if (pendingExitToReader) {
       pendingExitToReader = false;
@@ -353,25 +327,28 @@ void DictionaryWordSelectActivity::loop() {
     std::string cleaned = Dictionary::cleanWord(rawWord);
 
     if (cleaned.empty()) {
-      GUI.drawPopup(renderer, "No word");
-      renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+      {
+        Activity::RenderLock lock(*this);
+        GUI.drawPopup(renderer, "No word");
+        renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+      }
       vTaskDelay(1000 / portTICK_PERIOD_MS);
-      updateRequired = true;
+      requestUpdate();
       return;
     }
 
-    // Show looking up popup, then release mutex so display task can run
-    xSemaphoreTake(renderingMutex, portMAX_DELAY);
-    Rect popupLayout = GUI.drawPopup(renderer, "Looking up...");
-    xSemaphoreGive(renderingMutex);
+    Rect popupLayout;
+    {
+      Activity::RenderLock lock(*this);
+      popupLayout = GUI.drawPopup(renderer, "Looking up...");
+    }
 
     bool cancelled = false;
     std::string definition = Dictionary::lookup(
         cleaned,
         [this, &popupLayout](int percent) {
-          xSemaphoreTake(renderingMutex, portMAX_DELAY);
+          Activity::RenderLock lock(*this);
           GUI.fillPopupProgress(renderer, popupLayout, percent);
-          xSemaphoreGive(renderingMutex);
         },
         [this, &cancelled]() -> bool {
           mappedInput.update();
@@ -383,7 +360,7 @@ void DictionaryWordSelectActivity::loop() {
         });
 
     if (cancelled) {
-      updateRequired = true;
+      requestUpdate();
       return;
     }
 
@@ -417,10 +394,13 @@ void DictionaryWordSelectActivity::loop() {
       return;
     }
 
-    GUI.drawPopup(renderer, "Not found");
-    renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+    {
+      Activity::RenderLock lock(*this);
+      GUI.drawPopup(renderer, "Not found");
+      renderer.displayBuffer(HalDisplay::FAST_REFRESH);
+    }
     vTaskDelay(1500 / portTICK_PERIOD_MS);
-    updateRequired = true;
+    requestUpdate();
     return;
   }
 
@@ -430,11 +410,11 @@ void DictionaryWordSelectActivity::loop() {
   }
 
   if (changed) {
-    updateRequired = true;
+    requestUpdate();
   }
 }
 
-void DictionaryWordSelectActivity::renderScreen() {
+void DictionaryWordSelectActivity::render(Activity::RenderLock&&) {
   renderer.clearScreen();
 
   // Render the page content