Merge upstream/master and resolve conflicts

- Use StringUtils for file extension checks (upstream pattern)
- Keep screenMargin as uint8_t (upstream pattern)
- Add TXT file support to FileSelectionActivity and SleepActivity
- Use SETTINGS.textAntiAliasing for grayscale rendering

src/activities/reader/EpubReaderActivity.cpp

@@ -16,8 +16,6 @@ namespace {
 // pagesPerRefresh now comes from SETTINGS.getRefreshFrequency()
 constexpr unsigned long skipChapterMs = 700;
 constexpr unsigned long goHomeMs = 1000;
-constexpr int topPadding = 5;
-constexpr int horizontalPadding = 5;
 constexpr int statusBarMargin = 19;
 }  // namespace
 
@@ -253,9 +251,9 @@ void EpubReaderActivity::renderScreen() {
   int orientedMarginTop, orientedMarginRight, orientedMarginBottom, orientedMarginLeft;
   renderer.getOrientedViewableTRBL(&orientedMarginTop, &orientedMarginRight, &orientedMarginBottom,
                                    &orientedMarginLeft);
-  orientedMarginTop += topPadding;
-  orientedMarginLeft += horizontalPadding;
-  orientedMarginRight += horizontalPadding;
+  orientedMarginTop += SETTINGS.screenMargin;
+  orientedMarginLeft += SETTINGS.screenMargin;
+  orientedMarginRight += SETTINGS.screenMargin;
   orientedMarginBottom += statusBarMargin;
 
   if (!section) {
@@ -390,7 +388,7 @@ void EpubReaderActivity::renderContents(std::unique_ptr<Page> page, const int or
 
   // grayscale rendering
   // TODO: Only do this if font supports it
-  {
+  if (SETTINGS.textAntiAliasing) {
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
     page->render(renderer, SETTINGS.getReaderFontId(), orientedMarginLeft, orientedMarginTop);
@@ -439,7 +437,7 @@ void EpubReaderActivity::renderStatusBar(const int orientedMarginRight, const in
   }
 
   if (showBattery) {
-    ScreenComponents::drawBattery(renderer, orientedMarginLeft, textY);
+    ScreenComponents::drawBattery(renderer, orientedMarginLeft + 1, textY);
   }
 
   if (showChapterTitle) {

src/activities/reader/FileSelectionActivity.cpp

@@ -5,6 +5,7 @@
 
 #include "MappedInputManager.h"
 #include "fontIds.h"
+#include "util/StringUtils.h"
 
 namespace {
 constexpr int PAGE_ITEMS = 23;
@@ -29,7 +30,6 @@ void FileSelectionActivity::taskTrampoline(void* param) {
 
 void FileSelectionActivity::loadFiles() {
   files.clear();
-  selectorIndex = 0;
 
   auto root = SdMan.open(basepath.c_str());
   if (!root || !root.isDirectory()) {
@@ -39,7 +39,7 @@ void FileSelectionActivity::loadFiles() {
 
   root.rewindDirectory();
 
-  char name[128];
+  char name[500];
   for (auto file = root.openNextFile(); file; file = root.openNextFile()) {
     file.getName(name, sizeof(name));
     if (name[0] == '.' || strcmp(name, "System Volume Information") == 0) {
@@ -51,9 +51,8 @@ void FileSelectionActivity::loadFiles() {
       files.emplace_back(std::string(name) + "/");
     } else {
       auto filename = std::string(name);
-      std::string ext4 = filename.length() >= 4 ? filename.substr(filename.length() - 4) : "";
-      std::string ext5 = filename.length() >= 5 ? filename.substr(filename.length() - 5) : "";
-      if (ext5 == ".epub" || ext5 == ".xtch" || ext4 == ".xtc" || ext4 == ".txt") {
+      if (StringUtils::checkFileExtension(filename, ".epub") || StringUtils::checkFileExtension(filename, ".xtch") ||
+          StringUtils::checkFileExtension(filename, ".xtc") || StringUtils::checkFileExtension(filename, ".txt")) {
         files.emplace_back(filename);
       }
     }
@@ -124,6 +123,7 @@ void FileSelectionActivity::loop() {
     if (files[selectorIndex].back() == '/') {
       basepath += files[selectorIndex].substr(0, files[selectorIndex].length() - 1);
       loadFiles();
+      selectorIndex = 0;
       updateRequired = true;
     } else {
       onSelect(basepath + files[selectorIndex]);
@@ -132,9 +132,16 @@ void FileSelectionActivity::loop() {
     // Short press: go up one directory, or go home if at root
     if (mappedInput.getHeldTime() < GO_HOME_MS) {
       if (basepath != "/") {
+        const std::string oldPath = basepath;
+
         basepath.replace(basepath.find_last_of('/'), std::string::npos, "");
         if (basepath.empty()) basepath = "/";
         loadFiles();
+
+        const auto pos = oldPath.find_last_of('/');
+        const std::string dirName = oldPath.substr(pos + 1) + "/";
+        selectorIndex = findEntry(dirName);
+
         updateRequired = true;
       } else {
         onGoHome();
@@ -187,10 +194,16 @@ void FileSelectionActivity::render() const {
 
   const auto pageStartIndex = selectorIndex / PAGE_ITEMS * PAGE_ITEMS;
   renderer.fillRect(0, 60 + (selectorIndex % PAGE_ITEMS) * 30 - 2, pageWidth - 1, 30);
-  for (int i = pageStartIndex; i < files.size() && i < pageStartIndex + PAGE_ITEMS; i++) {
+  for (size_t i = pageStartIndex; i < files.size() && i < pageStartIndex + PAGE_ITEMS; i++) {
     auto item = renderer.truncatedText(UI_10_FONT_ID, files[i].c_str(), renderer.getScreenWidth() - 40);
     renderer.drawText(UI_10_FONT_ID, 20, 60 + (i % PAGE_ITEMS) * 30, item.c_str(), i != selectorIndex);
   }
 
   renderer.displayBuffer();
 }
+
+size_t FileSelectionActivity::findEntry(const std::string& name) const {
+  for (size_t i = 0; i < files.size(); i++)
+    if (files[i] == name) return i;
+  return 0;
+}

src/activities/reader/FileSelectionActivity.h

@@ -14,7 +14,7 @@ class FileSelectionActivity final : public Activity {
   SemaphoreHandle_t renderingMutex = nullptr;
   std::string basepath = "/";
   std::vector<std::string> files;
-  int selectorIndex = 0;
+  size_t selectorIndex = 0;
   bool updateRequired = false;
   const std::function<void(const std::string&)> onSelect;
   const std::function<void()> onGoHome;
@@ -24,6 +24,8 @@ class FileSelectionActivity final : public Activity {
   void render() const;
   void loadFiles();
 
+  size_t findEntry(const std::string& name) const;
+
  public:
   explicit FileSelectionActivity(GfxRenderer& renderer, MappedInputManager& mappedInput,
                                  const std::function<void(const std::string&)>& onSelect,

src/activities/reader/ReaderActivity.cpp

@@ -8,6 +8,7 @@
 #include "Xtc.h"
 #include "XtcReaderActivity.h"
 #include "activities/util/FullScreenMessageActivity.h"
+#include "util/StringUtils.h"
 
 std::string ReaderActivity::extractFolderPath(const std::string& filePath) {
   const auto lastSlash = filePath.find_last_of('/');
@@ -18,14 +19,7 @@ std::string ReaderActivity::extractFolderPath(const std::string& filePath) {
 }
 
 bool ReaderActivity::isXtcFile(const std::string& path) {
-  if (path.length() < 4) return false;
-  std::string ext4 = path.substr(path.length() - 4);
-  if (ext4 == ".xtc") return true;
-  if (path.length() >= 5) {
-    std::string ext5 = path.substr(path.length() - 5);
-    if (ext5 == ".xtch") return true;
-  }
-  return false;
+  return StringUtils::checkFileExtension(path, ".xtc") || StringUtils::checkFileExtension(path, ".xtch");
 }
 
 bool ReaderActivity::isTxtFile(const std::string& path) {

src/activities/reader/TxtReaderActivity.cpp

@@ -144,7 +144,7 @@ void TxtReaderActivity::initializeReader() {
 
   // Store current settings for cache validation
   cachedFontId = SETTINGS.getReaderFontId();
-  cachedScreenMargin = SETTINGS.getScreenMargin();
+  cachedScreenMargin = SETTINGS.screenMargin;
   cachedParagraphAlignment = SETTINGS.paragraphAlignment;
 
   // Calculate viewport dimensions
@@ -460,7 +460,7 @@ void TxtReaderActivity::renderPage() {
   renderer.storeBwBuffer();
 
   // Grayscale rendering pass (for anti-aliased fonts)
-  {
+  if (SETTINGS.textAntiAliasing) {
     renderer.clearScreen(0x00);
     renderer.setRenderMode(GfxRenderer::GRAYSCALE_LSB);
     renderLines();