Extract person handle comparison and fix remaining font constant

- Add _person_matches_handle() helper method to eliminate code duplication
- Replace 3 instances of 'person and person.get_handle() == handle' pattern
- Fix remaining hardcoded font string to use FONT_FAMILY constant
- Improve code consistency and maintainability

Benefits:
- Reduced code duplication
- Centralized person handle comparison logic
- All font strings now use constants
- More readable and maintainable code

MyTimeline.py

@@ -699,6 +699,19 @@ class MyTimelineView(NavigationView):
         
         return (min_date, max_date, date_range)
 
+    def _person_matches_handle(self, person: Optional[Any], handle: str) -> bool:
+        """
+        Check if a person's handle matches the given handle.
+        
+        Args:
+            person: The person object (may be None).
+            handle: The handle to match against.
+            
+        Returns:
+            bool: True if person exists and handle matches, False otherwise.
+        """
+        return person is not None and person.get_handle() == handle
+
     def _calculate_y_position(self, date_sort: int, min_date: int, date_range: int,
                               timeline_y_start: float, timeline_y_end: float) -> float:
         """
@@ -761,7 +774,9 @@ class MyTimelineView(NavigationView):
         
         # Create a temporary layout to measure text
         layout = PangoCairo.create_layout(context)
-        layout.set_font_description(Pango.font_description_from_string("Sans 11"))
+        layout.set_font_description(
+            Pango.font_description_from_string(f"{FONT_FAMILY} {FONT_SIZE_NORMAL}")
+        )
         
         adjusted_events = []
         
@@ -1224,7 +1239,7 @@ class MyTimelineView(NavigationView):
             # Find all events for this person
             person_events = [
                 evt for evt in self.events
-                if evt.person and evt.person.get_handle() == person_handle
+                if self._person_matches_handle(evt.person, person_handle)
             ]
             
             tooltip_text = self._format_person_tooltip(event_data.person, person_events)
@@ -1338,8 +1353,7 @@ class MyTimelineView(NavigationView):
             
             # Check if this event belongs to selected person
             is_selected = (self.selected_person_handle is not None and 
-                          event_data.person and 
-                          event_data.person.get_handle() == self.selected_person_handle)
+                          self._person_matches_handle(event_data.person, self.selected_person_handle))
             
             # Draw event marker with modern styling
             self.draw_event_marker(context, timeline_x, event_data.y_pos, 
@@ -1786,8 +1800,7 @@ class MyTimelineView(NavigationView):
         # Find all events for the selected person
         person_events = [
             event_data for event_data in events_with_y_pos
-            if event_data.person and 
-            event_data.person.get_handle() == self.selected_person_handle
+            if self._person_matches_handle(event_data.person, self.selected_person_handle)
         ]
         
         if len(person_events) < 1: