improvement: FDI tooth chart overhauled.

frontend/src/components/ui/treatment/TreatmentWorkspace.tsx

@@ -45,8 +45,12 @@ import {
   connectedTeethSet,
   deriveTeethFromGroups,
   groupsFromFlatTeeth,
+  linkAdjacentTeeth,
+  linkedEdgesFromGroups,
   pruneToothProsthesisForGroups,
+  toothEdgeKey,
   toggleToothInGroups,
+  unlinkAdjacentTeeth,
 } from '@/components/treatment/toothSelectionGroups';
 import type { LabDispatchAttentionItem } from '@/components/treatment/labDispatchAttention';
 import { collectLabDispatchAttention } from '@/components/treatment/labDispatchAttention';
@@ -614,6 +618,10 @@ export function TreatmentWorkspace({
     () => connectedTeethSet(activeDetail?.toothSelectionGroups ?? []),
     [activeDetail?.toothSelectionGroups],
   );
+  const linkedToothEdges = useMemo(
+    () => linkedEdgesFromGroups(activeDetail?.toothSelectionGroups ?? []),
+    [activeDetail?.toothSelectionGroups],
+  );
   const rangeAnchorRef = useRef<FdiToothId | null>(null);
 
   const wholePlanTeethSet = useMemo(() => {
@@ -2016,6 +2024,7 @@ export function TreatmentWorkspace({
           {entryStep === 'teeth' ? (
             <FdiToothChart
               selected={chartSelectedTeeth}
+              linkedEdges={showWholeTreatmentPlan ? undefined : linkedToothEdges}
               connectedTeeth={showWholeTreatmentPlan ? undefined : connectedSelectedTeeth}
               toothColors={chartToothColors}
               readOnly={showWholeTreatmentPlan}
@@ -2089,6 +2098,53 @@ export function TreatmentWorkspace({
                   }),
                 );
               }}
+              onToggleLink={(a, b) => {
+                if (
+                  !canEditTreatmentForDay ||
+                  isDetailLocked(activeDetail) ||
+                  showWholeTreatmentPlan ||
+                  !activeDetailId
+                ) {
+                  return;
+                }
+                const detail = details.find((d) => d.clientId === activeDetailId);
+                if (!detail) return;
+                const currentGroups =
+                  detail.toothSelectionGroups.length > 0
+                    ? detail.toothSelectionGroups
+                    : groupsFromFlatTeeth(detail.teeth);
+                const edgeLinked = linkedEdgesFromGroups(currentGroups).has(toothEdgeKey(a, b));
+                const nextGroups = edgeLinked
+                  ? unlinkAdjacentTeeth(currentGroups, a, b)
+                  : linkAdjacentTeeth(currentGroups, a, b);
+                if (!nextGroups) return;
+
+                setDetails((prev) =>
+                  prev.map((d) =>
+                    d.clientId !== activeDetailId
+                      ? d
+                      : {
+                          ...d,
+                          toothSelectionGroups: nextGroups,
+                          teeth: deriveTeethFromGroups(nextGroups),
+                        },
+                  ),
+                );
+
+                setLabCaseDrafts((prev) =>
+                  prev.map((lc) => {
+                    if (lc.detailClientId !== activeDetailId) return lc;
+                    return {
+                      ...lc,
+                      toothProsthesis: pruneToothProsthesisForGroups(
+                        lc.toothProsthesis,
+                        activeDetailId,
+                        nextGroups,
+                      ),
+                    };
+                  }),
+                );
+              }}
               disabled={!canEditTreatmentForDay || isDetailLocked(activeDetail)}
             />
           ) : null}