feat: add Trends sidebar nav item + 3-view switching (Task E.2)

dash_app/callbacks/navigation.py

@@ -1,4 +1,4 @@
-"""Callbacks for view switching between Patient Pathways and Trust Comparison."""
+"""Callbacks for view switching between Patient Pathways, Trust Comparison, and Trends."""
 from dash import Input, Output
 
 
@@ -8,22 +8,27 @@ def register_navigation_callbacks(app):
     @app.callback(
         Output("patient-pathways-view", "style"),
         Output("trust-comparison-view", "style"),
+        Output("trends-view", "style"),
         Output("nav-patient-pathways", "className"),
         Output("nav-trust-comparison", "className"),
+        Output("nav-trends", "className"),
         Input("app-state", "data"),
     )
     def switch_view(app_state):
         """Show/hide views and update sidebar active state based on active_view."""
-        if not app_state:
-            return {}, {"display": "none"}, "sidebar__item sidebar__item--active", "sidebar__item"
-
-        view = app_state.get("active_view", "patient-pathways")
         show = {}
         hide = {"display": "none"}
         active_cls = "sidebar__item sidebar__item--active"
         inactive_cls = "sidebar__item"
 
+        if not app_state:
+            return show, hide, hide, active_cls, inactive_cls, inactive_cls
+
+        view = app_state.get("active_view", "patient-pathways")
+
         if view == "patient-pathways":
-            return show, hide, active_cls, inactive_cls
-        else:
-            return hide, show, inactive_cls, active_cls
+            return show, hide, hide, active_cls, inactive_cls, inactive_cls
+        elif view == "trust-comparison":
+            return hide, show, hide, inactive_cls, active_cls, inactive_cls
+        else:  # trends
+            return hide, hide, show, inactive_cls, inactive_cls, active_cls