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/util/BookmarkStore.cpp

@@ -1,6 +1,7 @@
 #include "BookmarkStore.h"
 
 #include <HalStorage.h>
+#include <Logging.h>
 
 #include <algorithm>
 
@@ -78,7 +79,7 @@ std::vector<Bookmark> BookmarkStore::load(const std::string& cachePath) {
 bool BookmarkStore::save(const std::string& cachePath, const std::vector<Bookmark>& bookmarks) {
   FsFile f;
   if (!Storage.openFileForWrite("BKM", filePath(cachePath), f)) {
-    Serial.printf("[%lu] [BKM] Could not save bookmarks!\n", millis());
+    LOG_ERR("BKM", "Could not save bookmarks!");
     return false;
   }
 
@@ -107,7 +108,7 @@ bool BookmarkStore::save(const std::string& cachePath, const std::vector<Bookmar
   }
 
   f.close();
-  Serial.printf("[%lu] [BKM] Saved %d bookmarks\n", millis(), count);
+  LOG_DBG("BKM", "Saved %d bookmarks", count);
   return true;
 }