feat: add motion expander to compass tab — shows top motions per axis

explorer.py

@@ -1028,6 +1028,51 @@ def build_compass_tab(db_path: str, window_size: str) -> None:
         ):
             st.caption(_y_interp)
 
+        # Motion expander — show which motions define each axis for this window
+        x_top = axis_def.get("x_top_motions", {}).get(window_idx, {})
+        y_top = axis_def.get("y_top_motions", {}).get(window_idx, {})
+        x_conf = axis_def.get("x_label_confidence", {}).get(window_idx)
+        y_conf = axis_def.get("y_label_confidence", {}).get(window_idx)
+        evr = axis_def.get("explained_variance_ratio", [None, None])
+        evr0 = evr[0] if evr else None
+
+        _has_motion_data = bool(
+            x_top.get("+") or x_top.get("-") or y_top.get("+") or y_top.get("-")
+        )
+        if _has_motion_data:
+            with st.expander("\U0001f50d Wat bepaalt deze assen?"):
+                x_conf_pct = (
+                    f" (vertrouwen: {x_conf:.0%})" if x_conf is not None else ""
+                )
+                y_conf_pct = (
+                    f" (vertrouwen: {y_conf:.0%})" if y_conf is not None else ""
+                )
+
+                st.markdown(f"**Horizontale as: {_x_label}**{x_conf_pct}")
+                x_pos_titles = x_top.get("+", [])
+                x_neg_titles = x_top.get("-", [])
+                if x_pos_titles:
+                    labels_pos = " · ".join(f"{t} ({d})" for t, d in x_pos_titles[:3])
+                    st.markdown(f"  ➕ {labels_pos}")
+                if x_neg_titles:
+                    labels_neg = " · ".join(f"{t} ({d})" for t, d in x_neg_titles[:3])
+                    st.markdown(f"  ➖ {labels_neg}")
+
+                st.markdown(f"**Verticale as: {_y_label}**{y_conf_pct}")
+                y_pos_titles = y_top.get("+", [])
+                y_neg_titles = y_top.get("-", [])
+                if y_pos_titles:
+                    labels_pos = " · ".join(f"{t} ({d})" for t, d in y_pos_titles[:3])
+                    st.markdown(f"  ➕ {labels_pos}")
+                if y_neg_titles:
+                    labels_neg = " · ".join(f"{t} ({d})" for t, d in y_neg_titles[:3])
+                    st.markdown(f"  ➖ {labels_neg}")
+
+                if evr0 is not None:
+                    st.caption(
+                        f"As 1 verklaart {evr0:.1%} van de variantie in stemgedrag."
+                    )
+
     # --- Voting discipline section ---
     _MIN_MOTIONS_FOR_DISCIPLINE = 5
     start_date, end_date = _window_to_dates(window_idx)