Merge 6c31f7581c into f67c544e16

## Summary

Resolves #562 

Implements regex change to support valid characters discussed by
@daveallie in issue
[here](https://github.com/crosspoint-reader/crosspoint-reader/issues/562#issuecomment-3830809156).

Also rejects `.` and `..` as folder names which are invalid in FAT32 and
exFAT filesystems

## Additional Context
- Unsure on the wording for the alert, it feels overly explicit, but
that might be a good thing. Happy to change.

---

### AI Usage

While CrossPoint doesn't have restrictions on AI tools in contributing,
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 >**_

docs/webserver.md

@@ -153,7 +153,7 @@ Click **File Manager** to access file management features.
 
 1. Click the **+ Add** button in the top-right corner
 2. Select **New Folder** from the dropdown menu
-3. Enter a folder name (letters, numbers, underscores, and hyphens only)
+3. Enter a folder name (must not contain characters \" * : < > ? / \\ | and must not be . or ..)
 4. Click **Create Folder**
 
 This is useful for organizing your ebooks by genre, author, or series.

src/CrossPointSettings.h

@@ -15,7 +15,7 @@ class CrossPointSettings {
   CrossPointSettings(const CrossPointSettings&) = delete;
   CrossPointSettings& operator=(const CrossPointSettings&) = delete;
 
-  enum SLEEP_SCREEN_MODE { DARK = 0, LIGHT = 1, CUSTOM = 2, COVER = 3, BLANK = 4, SLEEP_SCREEN_MODE_COUNT };
+  enum SLEEP_SCREEN_MODE { DARK = 0, LIGHT = 1, CUSTOM = 2, COVER = 3, COVERELSECUSTOM = 4, BLANK = 5, SLEEP_SCREEN_MODE_COUNT };
   enum SLEEP_SCREEN_COVER_MODE { FIT = 0, CROP = 1, SLEEP_SCREEN_COVER_MODE_COUNT };
   enum SLEEP_SCREEN_COVER_FILTER {
     NO_FILTER = 0,

src/activities/boot_sleep/SleepActivity.cpp

@@ -30,6 +30,10 @@ void SleepActivity::onEnter() {
     return renderCoverSleepScreen();
   }
 
+  if (SETTINGS.sleepScreen == CrossPointSettings::SLEEP_SCREEN_MODE::COVERELSECUSTOM) {
+    return renderCoverElseCustomSleepScreen();
+  }
+
   renderDefaultSleepScreen();
 }
 
@@ -266,6 +270,75 @@ void SleepActivity::renderCoverSleepScreen() const {
   renderDefaultSleepScreen();
 }
 
+void SleepActivity::renderCoverElseCustomSleepScreen() const {
+  if (APP_STATE.openEpubPath.empty()) {
+    return renderCustomSleepScreen();
+  }
+
+  std::string coverBmpPath;
+  bool cropped = SETTINGS.sleepScreenCoverMode == CrossPointSettings::SLEEP_SCREEN_COVER_MODE::CROP;
+
+  // Check if the current book is XTC, TXT, or EPUB
+  if (StringUtils::checkFileExtension(APP_STATE.openEpubPath, ".xtc") ||
+      StringUtils::checkFileExtension(APP_STATE.openEpubPath, ".xtch")) {
+    // Handle XTC file
+    Xtc lastXtc(APP_STATE.openEpubPath, "/.crosspoint");
+    if (!lastXtc.load()) {
+      Serial.println("[SLP] Failed to load last XTC");
+      return renderCustomSleepScreen();
+    }
+
+    if (!lastXtc.generateCoverBmp()) {
+      Serial.println("[SLP] Failed to generate XTC cover bmp");
+      return renderCustomSleepScreen();
+    }
+
+    coverBmpPath = lastXtc.getCoverBmpPath();
+  } else if (StringUtils::checkFileExtension(APP_STATE.openEpubPath, ".txt")) {
+    // Handle TXT file - looks for cover image in the same folder
+    Txt lastTxt(APP_STATE.openEpubPath, "/.crosspoint");
+    if (!lastTxt.load()) {
+      Serial.println("[SLP] Failed to load last TXT");
+      return renderCustomSleepScreen();
+    }
+
+    if (!lastTxt.generateCoverBmp()) {
+      Serial.println("[SLP] No cover image found for TXT file");
+      return renderCustomSleepScreen();
+    }
+
+    coverBmpPath = lastTxt.getCoverBmpPath();
+  } else if (StringUtils::checkFileExtension(APP_STATE.openEpubPath, ".epub")) {
+    // Handle EPUB file
+    Epub lastEpub(APP_STATE.openEpubPath, "/.crosspoint");
+    if (!lastEpub.load()) {
+      Serial.println("[SLP] Failed to load last epub");
+      return renderCustomSleepScreen();
+    }
+
+    if (!lastEpub.generateCoverBmp(cropped)) {
+      Serial.println("[SLP] Failed to generate cover bmp");
+      return renderCustomSleepScreen();
+    }
+
+    coverBmpPath = lastEpub.getCoverBmpPath(cropped);
+  } else {
+    return renderCustomSleepScreen();
+  }
+
+  FsFile file;
+  if (SdMan.openFileForRead("SLP", coverBmpPath, file)) {
+    Bitmap bitmap(file);
+    if (bitmap.parseHeaders() == BmpReaderError::Ok) {
+      Serial.printf("[SLP] Rendering sleep cover: %s\n", coverBmpPath);
+      renderBitmapSleepScreen(bitmap);
+      return;
+    }
+  }
+
+  renderCustomSleepScreen();
+}
+
 void SleepActivity::renderBlankSleepScreen() const {
   renderer.clearScreen();
   renderer.displayBuffer(HalDisplay::HALF_REFRESH);

src/activities/boot_sleep/SleepActivity.h

@@ -13,6 +13,7 @@ class SleepActivity final : public Activity {
   void renderDefaultSleepScreen() const;
   void renderCustomSleepScreen() const;
   void renderCoverSleepScreen() const;
+  void renderCoverElseCustomSleepScreen() const;
   void renderBitmapSleepScreen(const Bitmap& bitmap) const;
   void renderBlankSleepScreen() const;
 };

src/activities/settings/SettingsActivity.cpp

@@ -14,7 +14,7 @@ namespace {
 constexpr int displaySettingsCount = 6;
 const SettingInfo displaySettings[displaySettingsCount] = {
     // Should match with SLEEP_SCREEN_MODE
-    SettingInfo::Enum("Sleep Screen", &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover", "None"}),
+    SettingInfo::Enum("Sleep Screen", &CrossPointSettings::sleepScreen, {"Dark", "Light", "Custom", "Cover", "Cover else Custom", "None"}),
     SettingInfo::Enum("Sleep Screen Cover Mode", &CrossPointSettings::sleepScreenCoverMode, {"Fit", "Crop"}),
     SettingInfo::Enum("Sleep Screen Cover Filter", &CrossPointSettings::sleepScreenCoverFilter,
                       {"None", "Contrast", "Inverted"}),

src/network/html/FilesPage.html

@@ -1146,10 +1146,10 @@ function retryAllFailedUploads() {
       return;
     }
 
-    // Validate folder name (no special characters except underscore and hyphen)
+    // Validate folder name
-    const validName = /^[a-zA-Z0-9_\-]+$/.test(folderName);
+    const validName = /^(?!\.{1,2}$)[^"*:<>?\/\\|]+$/.test(folderName);
     if (!validName) {
-      alert('Folder name can only contain letters, numbers, underscores, and hyphens.');
+      alert('Folder name cannot contain \" * : < > ? / \\ | and must not be . or ..');
       return;
     }