fix: prevent Serial.printf from blocking when USB disconnected

On ESP32-C3 with USB CDC, Serial.printf() blocks indefinitely when USB
is not connected. This caused device freezes when booted without USB.

Solution: Call Serial.setTxTimeoutMs(0) after Serial.begin() to make
all Serial output non-blocking.

Also added if (Serial) guards to high-traffic logging paths in
EpubReaderActivity as belt-and-suspenders protection.

Includes documentation of the debugging process and Serial call inventory.

Also applies clang-format to fix pre-existing formatting issues.

lib/StarDict/DictHtmlParser.cpp

@@ -150,8 +150,7 @@ std::string DictHtmlParser::extractTagName(const std::string& html, size_t start
 
   std::string tagName = html.substr(nameStart, pos - nameStart);
   // Convert to lowercase
-  std::transform(tagName.begin(), tagName.end(), tagName.begin(),
-                 [](unsigned char c) { return std::tolower(c); });
+  std::transform(tagName.begin(), tagName.end(), tagName.begin(), [](unsigned char c) { return std::tolower(c); });
   return tagName;
 }
 
@@ -160,17 +159,11 @@ bool DictHtmlParser::isBlockTag(const std::string& tagName) {
          tagName == "ol" || tagName == "ul" || tagName == "dt" || tagName == "dd" || tagName == "html";
 }
 
-bool DictHtmlParser::isBoldTag(const std::string& tagName) {
-  return tagName == "b" || tagName == "strong";
-}
+bool DictHtmlParser::isBoldTag(const std::string& tagName) { return tagName == "b" || tagName == "strong"; }
 
-bool DictHtmlParser::isItalicTag(const std::string& tagName) {
-  return tagName == "i" || tagName == "em";
-}
+bool DictHtmlParser::isItalicTag(const std::string& tagName) { return tagName == "i" || tagName == "em"; }
 
-bool DictHtmlParser::isUnderlineTag(const std::string& tagName) {
-  return tagName == "u" || tagName == "ins";
-}
+bool DictHtmlParser::isUnderlineTag(const std::string& tagName) { return tagName == "u" || tagName == "ins"; }
 
 bool DictHtmlParser::isSuperscriptTag(const std::string& tagName) { return tagName == "sup"; }
 

lib/StarDict/DictHtmlParser.h

@@ -10,7 +10,7 @@ class GfxRenderer;
 
 /**
  * DictHtmlParser parses HTML dictionary definitions into ParsedText.
- * 
+ *
  * Supports:
  * - Bold: <b>, <strong>
  * - Italic: <i>, <em>
@@ -25,7 +25,7 @@ class DictHtmlParser {
   /**
    * Parse HTML definition and populate ParsedText with styled words.
    * Each paragraph/block creates a separate ParsedText via the callback.
-   * 
+   *
    * @param html The HTML definition text
    * @param fontId Font ID for text width calculations
    * @param renderer Reference to renderer for layout

lib/StarDict/StarDict.cpp

@@ -588,8 +588,12 @@ static std::string decodeHtmlEntity(const std::string& html, size_t& i) {
       const char* replacement;
     };
     static const EntityMapping entities[] = {
-        {"&nbsp;", " "},      {"&lt;", "<"},        {"&gt;", ">"},
-        {"&amp;", "&"},       {"&quot;", "\""},     {"&apos;", "'"},
+        {"&nbsp;", " "},
+        {"&lt;", "<"},
+        {"&gt;", ">"},
+        {"&amp;", "&"},
+        {"&quot;", "\""},
+        {"&apos;", "'"},
         {"&mdash;", "\xe2\x80\x94"},   // —
         {"&ndash;", "\xe2\x80\x93"},   // –
         {"&hellip;", "\xe2\x80\xa6"},  // …
@@ -688,8 +692,8 @@ std::string StarDict::stripHtml(const std::string& html) {
 
       // Extract tag name
       size_t tagEnd = tagStart;
-      while (tagEnd < html.length() && !std::isspace(static_cast<unsigned char>(html[tagEnd])) &&
-             html[tagEnd] != '>' && html[tagEnd] != '/') {
+      while (tagEnd < html.length() && !std::isspace(static_cast<unsigned char>(html[tagEnd])) && html[tagEnd] != '>' &&
+             html[tagEnd] != '/') {
         tagEnd++;
       }
 

lib/StarDict/StarDict.h

@@ -32,7 +32,7 @@ class StarDict {
   struct DictzipInfo {
     uint32_t chunkLength = 0;  // Uncompressed chunk size (usually 58315)
     uint16_t chunkCount = 0;
-    uint32_t headerSize = 0;   // Total header size to skip
+    uint32_t headerSize = 0;         // Total header size to skip
     uint16_t* chunkSizes = nullptr;  // Array of compressed chunk sizes
     bool loaded = false;
   };