feat: port upstream PRs #852, #965, #972, #971, #977, #975

Port 6 upstream PRs (PR #939 was already ported):

- #852: Complete HalPowerManager with RAII Lock class, WiFi check in
  setPowerSaving, skipLoopDelay overrides for ClearCache/OtaUpdate,
  and power lock in Activity render task loops
- #965: Fix paragraph formatting inside list items by tracking
  listItemUntilDepth to prevent unwanted line breaks
- #972: Micro-optimizations: std::move in insertFont, const ref for
  getDataFromBook parameter
- #971: Remove redundant hasPrintableChars pre-rendering pass from
  EpdFont, EpdFontFamily, and GfxRenderer
- #977: Skip unsupported image formats before extraction, add
  PARSE_BUFFER_SIZE constant and chapter parse timing
- #975: Fix UITheme memory leak by replacing raw pointer with
  std::unique_ptr for currentTheme

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/EpdFont/EpdFont.cpp

@@ -47,14 +47,6 @@ void EpdFont::getTextDimensions(const char* string, int* w, int* h) const {
   *h = maxY - minY;
 }
 
-bool EpdFont::hasPrintableChars(const char* string) const {
-  int w = 0, h = 0;
-
-  getTextDimensions(string, &w, &h);
-
-  return w > 0 || h > 0;
-}
-
 const EpdGlyph* EpdFont::getGlyph(const uint32_t cp) const {
   const EpdUnicodeInterval* intervals = data->intervals;
   const int count = data->intervalCount;

lib/EpdFont/EpdFont.h

@@ -9,7 +9,6 @@ class EpdFont {
   explicit EpdFont(const EpdFontData* data) : data(data) {}
   ~EpdFont() = default;
   void getTextDimensions(const char* string, int* w, int* h) const;
-  bool hasPrintableChars(const char* string) const;
 
   const EpdGlyph* getGlyph(uint32_t cp) const;
 };

lib/EpdFont/EpdFontFamily.cpp

@@ -22,10 +22,6 @@ void EpdFontFamily::getTextDimensions(const char* string, int* w, int* h, const
   getFont(style)->getTextDimensions(string, w, h);
 }
 
-bool EpdFontFamily::hasPrintableChars(const char* string, const Style style) const {
-  return getFont(style)->hasPrintableChars(string);
-}
-
 const EpdFontData* EpdFontFamily::getData(const Style style) const { return getFont(style)->data; }
 
 const EpdGlyph* EpdFontFamily::getGlyph(const uint32_t cp, const Style style) const {

lib/EpdFont/EpdFontFamily.h

@@ -10,7 +10,6 @@ class EpdFontFamily {
       : regular(regular), bold(bold), italic(italic), boldItalic(boldItalic) {}
   ~EpdFontFamily() = default;
   void getTextDimensions(const char* string, int* w, int* h, Style style = REGULAR) const;
-  bool hasPrintableChars(const char* string, Style style = REGULAR) const;
   const EpdFontData* getData(Style style = REGULAR) const;
   const EpdGlyph* getGlyph(uint32_t cp, Style style = REGULAR) const;