Improve docs and security defaults

src/core/SeriesApp.py

@@ -241,7 +241,9 @@ class SeriesApp:
                     message="Download cancelled before starting"
                 )
             
-            # Wrap callback to check for cancellation and report progress
+            # Wrap callback to enforce cancellation checks and bridge the new
+            # event-driven progress reporting with the legacy callback API that
+            # the CLI still relies on.
             def wrapped_callback(progress: float):
                 if self._is_cancelled():
                     raise InterruptedError("Download cancelled by user")
@@ -268,6 +270,9 @@ class SeriesApp:
                 if callback:
                     callback(progress)
                 
+                # Propagate progress into the legacy callback chain so existing
+                # UI surfaces continue to receive updates without rewriting the
+                # old interfaces.
                 # Call legacy progress_callback if provided
                 if self.progress_callback:
                     self.progress_callback(ProgressInfo(
@@ -403,7 +408,9 @@ class SeriesApp:
             # Reinitialize scanner
             self.SerieScanner.reinit()
             
-            # Wrap callback for progress reporting and cancellation
+            # Wrap the scanner callback so we can surface progress through the
+            # new ProgressInfo pipeline while maintaining backwards
+            # compatibility with the legacy tuple-based callback signature.
             def wrapped_callback(folder: str, current: int):
                 if self._is_cancelled():
                     raise InterruptedError("Scan cancelled by user")