refactor: Removed redundant FsFile close() calls (#1434)

## Summary

**What is the goal of this PR?** (e.g., Implements the new feature for
file uploading.)

`DESTRUCTOR_CLOSES_FILE=1` is set in platformio.ini, which makes SdFat's
FsBaseFile destructor call close() automatically when a file goes out of
scope.

Three categories of file close calls remain untouched:
1. Close before Storage.remove() on the same path: ScreenshotUtil.cpp
closes the file before deleting it on write error. The remove might fail
if the file is still open.
2. Close before reopening the same variable: Epub.cpp writes a temp
NCX/nav file, closes it, then reopens it for reading. The
RecentBooksStore.cpp close before saveToFile() is the same pattern, it
rewrites the same file.
3. Close on member variables: BookMetadataCache.cpp (bookFile,
spineFile, tocFile), Section.cpp (file), XtcParser.cpp (m_file),
ZipFile.cpp (file). These persist beyond any single function scope, so
the destructor timing doesn't match the intended close point.

---

### AI Usage

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please be transparent about their usage as it
helps set the right context for reviewers.

Did you use AI tools to help write this code? _**PARTIALLY**_

src/activities/boot_sleep/SleepActivity.cpp

@@ -43,7 +43,6 @@ void SleepActivity::renderCustomSleepScreen() const {
   if (dir && dir.isDirectory()) {
     sleepDir = "/.sleep";
   } else {
-    if (dir) dir.close();
     dir = Storage.open("/sleep");
     if (dir && dir.isDirectory()) {
       sleepDir = "/sleep";
@@ -56,29 +55,24 @@ void SleepActivity::renderCustomSleepScreen() const {
     // collect all valid BMP files
     for (auto file = dir.openNextFile(); file; file = dir.openNextFile()) {
       if (file.isDirectory()) {
-        file.close();
         continue;
       }
       file.getName(name, sizeof(name));
       auto filename = std::string(name);
       if (filename[0] == '.') {
-        file.close();
         continue;
       }
 
       if (!FsHelpers::hasBmpExtension(filename)) {
         LOG_DBG("SLP", "Skipping non-.bmp file name: %s", name);
-        file.close();
         continue;
       }
       Bitmap bitmap(file);
       if (bitmap.parseHeaders() != BmpReaderError::Ok) {
         LOG_DBG("SLP", "Skipping invalid BMP file: %s", name);
-        file.close();
         continue;
       }
       files.emplace_back(filename);
-      file.close();
     }
     const auto numFiles = files.size();
     if (numFiles > 0) {
@@ -98,16 +92,11 @@ void SleepActivity::renderCustomSleepScreen() const {
         Bitmap bitmap(file, true);
         if (bitmap.parseHeaders() == BmpReaderError::Ok) {
           renderBitmapSleepScreen(bitmap);
-          file.close();
-          dir.close();
           return;
         }
-        file.close();
       }
     }
   }
-  if (dir) dir.close();
-
   // Look for sleep.bmp on the root of the sd card to determine if we should
   // render a custom sleep screen instead of the default.
   FsFile file;
@@ -116,10 +105,8 @@ void SleepActivity::renderCustomSleepScreen() const {
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       LOG_DBG("SLP", "Loading: /sleep.bmp");
       renderBitmapSleepScreen(bitmap);
-      file.close();
       return;
     }
-    file.close();
   }
 
   renderDefaultSleepScreen();
@@ -286,10 +273,8 @@ void SleepActivity::renderCoverSleepScreen() const {
     if (bitmap.parseHeaders() == BmpReaderError::Ok) {
       LOG_DBG("SLP", "Rendering sleep cover: %s", coverBmpPath.c_str());
       renderBitmapSleepScreen(bitmap);
-      file.close();
       return;
     }
-    file.close();
   }
 
   return (this->*renderNoCoverSleepScreen)();

src/activities/home/FileBrowserActivity.cpp

@@ -75,7 +75,6 @@ void FileBrowserActivity::loadFiles() {
 
   auto root = Storage.open(basepath.c_str());
   if (!root || !root.isDirectory()) {
-    if (root) root.close();
     return;
   }
 
@@ -85,7 +84,6 @@ void FileBrowserActivity::loadFiles() {
   for (auto file = root.openNextFile(); file; file = root.openNextFile()) {
     file.getName(name, sizeof(name));
     if ((!SETTINGS.showHiddenFiles && name[0] == '.') || strcmp(name, "System Volume Information") == 0) {
-      file.close();
       continue;
     }
 
@@ -99,9 +97,7 @@ void FileBrowserActivity::loadFiles() {
         files.emplace_back(filename);
       }
     }
-    file.close();
   }
-  root.close();
   sortFileList(files);
 }
 
@@ -115,7 +111,6 @@ void FileBrowserActivity::onEnter() {
     basepath = "/";
     loadFiles();
   } else if (!root.isDirectory()) {
-    root.close();
     lockLongPressBack = mappedInput.isPressed(MappedInputManager::Button::Back);
 
     const std::string oldPath = basepath;
@@ -126,7 +121,6 @@ void FileBrowserActivity::onEnter() {
     const std::string fileName = oldPath.substr(pos + 1);
     selectorIndex = findEntry(fileName);
   } else {
-    root.close();
     loadFiles();
   }
 

src/activities/reader/EpubReaderActivity.cpp

@@ -69,7 +69,6 @@ void EpubReaderActivity::onEnter() {
     if (dataSize == 6) {
       cachedChapterTotalPageCount = data[4] + (data[5] << 8);
     }
-    f.close();
   }
   // We may want a better condition to detect if we are opening for the first time.
   // This will trigger if the book is re-opened at Chapter 0.
@@ -696,7 +695,6 @@ void EpubReaderActivity::saveProgress(int spineIndex, int currentPage, int pageC
     data[4] = pageCount & 0xFF;
     data[5] = (pageCount >> 8) & 0xFF;
     f.write(data, 6);
-    f.close();
     LOG_DBG("ERS", "Progress saved: Chapter %d, Page %d", spineIndex, currentPage);
   } else {
     LOG_ERR("ERS", "Could not save progress!");

src/activities/reader/TxtReaderActivity.cpp

@@ -405,7 +405,6 @@ void TxtReaderActivity::saveProgress() const {
     data[2] = 0;
     data[3] = 0;
     f.write(data, 4);
-    f.close();
   }
 }
 
@@ -423,7 +422,6 @@ void TxtReaderActivity::loadProgress() {
       }
       LOG_DBG("TRS", "Loaded progress: page %d/%d", currentPage, totalPages);
     }
-    f.close();
   }
 }
 
@@ -452,7 +450,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, magic);
   if (magic != CACHE_MAGIC) {
     LOG_DBG("TRS", "Cache magic mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -460,7 +457,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, version);
   if (version != CACHE_VERSION) {
     LOG_DBG("TRS", "Cache version mismatch (%d != %d), rebuilding", version, CACHE_VERSION);
-    f.close();
     return false;
   }
 
@@ -468,7 +464,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, fileSize);
   if (fileSize != txt->getFileSize()) {
     LOG_DBG("TRS", "Cache file size mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -476,7 +471,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, cachedWidth);
   if (cachedWidth != viewportWidth) {
     LOG_DBG("TRS", "Cache viewport width mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -484,7 +478,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, cachedLines);
   if (cachedLines != linesPerPage) {
     LOG_DBG("TRS", "Cache lines per page mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -492,7 +485,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, fontId);
   if (fontId != cachedFontId) {
     LOG_DBG("TRS", "Cache font ID mismatch (%d != %d), rebuilding", fontId, cachedFontId);
-    f.close();
     return false;
   }
 
@@ -500,7 +492,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, margin);
   if (margin != cachedScreenMargin) {
     LOG_DBG("TRS", "Cache screen margin mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -508,7 +499,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
   serialization::readPod(f, alignment);
   if (alignment != cachedParagraphAlignment) {
     LOG_DBG("TRS", "Cache paragraph alignment mismatch, rebuilding");
-    f.close();
     return false;
   }
 
@@ -525,7 +515,6 @@ bool TxtReaderActivity::loadPageIndexCache() {
     pageOffsets.push_back(offset);
   }
 
-  f.close();
   totalPages = pageOffsets.size();
   LOG_DBG("TRS", "Loaded page index cache: %d pages", totalPages);
   return true;
@@ -555,6 +544,5 @@ void TxtReaderActivity::savePageIndexCache() const {
     serialization::writePod(f, static_cast<uint32_t>(offset));
   }
 
-  f.close();
   LOG_DBG("TRS", "Saved page index cache: %d pages", totalPages);
 }