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

dash_app/callbacks/filters.py

@@ -75,13 +75,14 @@ def register_filter_callbacks(app):
         Input("trust-chips", "value"),
         Input("nav-patient-pathways", "n_clicks"),
         Input("nav-trust-comparison", "n_clicks"),
+        Input("nav-trends", "n_clicks"),
         Input({"type": "tc-selector", "index": ALL}, "n_clicks"),
         Input("tc-back-btn", "n_clicks"),
         State("app-state", "data"),
     )
     def update_app_state(
         _dir_clicks, _ind_clicks, initiated, last_seen, selected_drugs,
-        selected_trusts, _nav_pp_clicks, _nav_tc_clicks,
+        selected_trusts, _nav_pp_clicks, _nav_tc_clicks, _nav_trends_clicks,
         _tc_selector_clicks, _tc_back_clicks, current_state
     ):
         """Update app-state when any filter, nav, or TC selector changes."""
@@ -96,6 +97,7 @@ def register_filter_callbacks(app):
                 "selected_trusts": [],
                 "active_view": "patient-pathways",
                 "selected_comparison_directorate": None,
+                "selected_trends_directorate": None,
             }
 
         triggered_id = ctx.triggered_id
@@ -114,6 +116,8 @@ def register_filter_callbacks(app):
             active_view = "patient-pathways"
         elif triggered_id == "nav-trust-comparison":
             active_view = "trust-comparison"
+        elif triggered_id == "nav-trends":
+            active_view = "trends"
 
         # Trust Comparison directorate selection
         selected_comparison_directorate = current_state.get("selected_comparison_directorate")

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