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>

tests/tst_visibility.cpp

@@ -79,7 +79,7 @@ private Q_SLOTS:
         v.show();
         QVERIFY(!v.isVisible());
         v.hide();
-        v.setEnabled(true); // turning it back on forgets the dismiss
+        v.setEnabled(true); // re-enabling clears the earlier hide()
         QVERIFY(v.isVisible());
     }