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>

src/RecentBooksStore.cpp

@@ -85,7 +85,7 @@ bool RecentBooksStore::saveToFile() const {
   return true;
 }
 
-RecentBook RecentBooksStore::getDataFromBook(std::string path) const {
+RecentBook RecentBooksStore::getDataFromBook(const std::string& path) const {
   std::string lastBookFileName = "";
   const size_t lastSlash = path.find_last_of('/');
   if (lastSlash != std::string::npos) {