Reword code comments in plain technical language

Comments only, no code changes. Replaces vague or personified phrasing
with explicit statements of what the code does and why, uses bullet
lists for multi-case behavior, and fixes the settings path in
WindowSettings.h (~/.config/sloposk/sloposk.conf).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

qml/SettingsButton.qml

@@ -5,7 +5,7 @@ Item {
     id: button
 
     property bool checked: false
-    // Something doesn't work (see Diagnostics): a dot invites a look in settings.
+    // Shows a dot when Diagnostics reports a problem.
     property bool alert: false
     signal clicked()