merge upstream/master: logging pragma, screenshot retrieval, nbsp fix

Merge 3 upstream commits into mod/master:
- feat: Allow screenshot retrieval from device (#820)
- feat: Add central logging pragma (#843)
- fix: Account for nbsp character as non-breaking space (#757)

Conflict resolution:
- src/main.cpp: kept mod's HalPowerManager + upstream's Logging/screenshot
- SleepActivity.cpp: kept mod's letterbox fill rework, applied LOG_* pattern

Additional changes for logging compatibility:
- Converted remaining Serial.printf calls in mod files to LOG_* macros
  (HalPowerManager, BookSettings, BookmarkStore, GfxRenderer)
- Added ENABLE_SERIAL_LOG and LOG_LEVEL=2 to [env:mod] build flags

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

src/CrossPointSettings.cpp

@@ -1,7 +1,7 @@
 #include "CrossPointSettings.h"
 
 #include <HalStorage.h>
-#include <HardwareSerial.h>
+#include <Logging.h>
 #include <Serialization.h>
 
 #include <cstring>
@@ -122,7 +122,7 @@ bool CrossPointSettings::saveToFile() const {
   // New fields added at end for backward compatibility
   outputFile.close();
 
-  Serial.printf("[%lu] [CPS] Settings saved to file\n", millis());
+  LOG_DBG("CPS", "Settings saved to file");
   return true;
 }
 
@@ -135,7 +135,7 @@ bool CrossPointSettings::loadFromFile() {
   uint8_t version;
   serialization::readPod(inputFile, version);
   if (version != SETTINGS_FILE_VERSION) {
-    Serial.printf("[%lu] [CPS] Deserialization failed: Unknown version %u\n", millis(), version);
+    LOG_ERR("CPS", "Deserialization failed: Unknown version %u", version);
     inputFile.close();
     return false;
   }
@@ -238,7 +238,7 @@ bool CrossPointSettings::loadFromFile() {
   }
 
   inputFile.close();
-  Serial.printf("[%lu] [CPS] Settings loaded from file\n", millis());
+  LOG_DBG("CPS", "Settings loaded from file");
   return true;
 }