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/components/UITheme.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <functional>
+#include <memory>
 #include <vector>
 
 #include "CrossPointSettings.h"
@@ -24,7 +25,7 @@ class UITheme {
 
  private:
   const ThemeMetrics* currentMetrics;
-  const BaseTheme* currentTheme;
+  std::unique_ptr<const BaseTheme> currentTheme;
 };
 
 // Known theme thumbnail heights to prerender when opening a book for the first time.