fix(canvas): apply the drag rank on the group, not inside it

Drag-to-front lifted boards but never parts: a component's z lives
inside .component-interactive-group, which is itself a stacking
context, so the 10+rank set on the inner wrapper was clamped to the
group's own level (1/2) while boards compete one level up as direct
children of .canvas-world. Once any board had been dragged it sat at
10+rank and no component could ever climb back over it — drag an LED
onto the Arduino and the board swallowed it, exactly as reported.

The rank now lands on the group itself (both branches: instruments and
ordinary parts), so parts and boards share ONE rank space and the last
thing dragged really is the thing on top. The inner wrapper keeps its
local 1/5 for selection order within the group.

frontend/src/components/DynamicComponent.tsx

@@ -295,10 +295,6 @@ export const DynamicComponent: React.FC<DynamicComponentProps> = ({
   const handleComponentEvent = useSimulatorStore((s) => s.handleComponentEvent);
   const running = useSimulatorStore((s) => s.running);
   const simulator = useSimulatorStore((s) => s.simulator);
-  // Drag-to-front rank: 0 = never dragged, static layering applies. A part
-  // the user dragged paints above everything it overlaps — including a board
-  // that was raised earlier — so the stack always reads "last dragged wins".
-  const zRaise = useSimulatorStore((s) => s.zOrders[id] ?? 0);
   // Board-less SPICE circuits (digital / analog gallery) have no MCU to
   // run, so `running` is always false — but interactive parts like
   // slide-switches and pushbuttons should still show a pointer cursor
@@ -810,7 +806,11 @@ export const DynamicComponent: React.FC<DynamicComponentProps> = ({
         // Drag-to-front (zRaise) beats the static layers: a part dragged onto
         // a board — or a board dragged onto a part — the last one dragged
         // paints on top. Untouched parts keep the classic selected/idle z.
-        zIndex: zRaise > 0 ? 10 + zRaise : isSelected ? 5 : 1,
+        // Local order inside .component-interactive-group only. The
+        // drag-to-front rank is applied on that GROUP (SimulatorCanvas) —
+        // a z set here is clamped by the group's stacking context and could
+        // never lift the part above a dragged board.
+        zIndex: isSelected ? 5 : 1,
         pointerEvents: 'auto',
         transform: properties.rotation ? `rotate(${properties.rotation}deg)` : undefined,
         transformOrigin: 'center center',

frontend/src/components/simulator/SimulatorCanvas.tsx

@@ -156,6 +156,7 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
     setBoardPosition,
     addBoard,
     components,
+    zOrders,
     running,
     sensorResetNonce,
     pinManager,
@@ -2314,7 +2315,13 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
               position: 'absolute',
               left: 0,
               top: 0,
-              zIndex: isSelected ? 2 : 1,
+              // Drag-to-front rank applies HERE (the group is the stacking
+              // context that competes with boards) — see the parts branch.
+              zIndex: (zOrders[component.id] ?? 0) > 0
+                ? 10 + (zOrders[component.id] ?? 0)
+                : isSelected
+                  ? 2
+                  : 1,
               pointerEvents: 'auto',
             }}
           >
@@ -2376,15 +2383,25 @@ export const SimulatorCanvas = ({ headerSlot }: SimulatorCanvasProps = {}) => {
     // thin parts (resistors, LEDs) and free-floating displays are untouched.
     const isSeated = (seatedPinsByComponent.get(component.id)?.length ?? 0) > 0;
     const occludesWhenSeated = DISPLAY_BODY_METADATA_RE.test(String(component.metadataId));
+    // Drag-to-front (see raiseItem): the rank MUST be applied on this group,
+    // not on the inner .dynamic-component-wrapper. The group is a stacking
+    // context, so a z set inside it is clamped to the group's own level and a
+    // part could never climb above a board that was dragged (boards live one
+    // level up, as direct children of .canvas-world) — dragging a board once
+    // pinned every component under it forever. Same rank space as
+    // BoardOnCanvas (10 + rank) so the last thing dragged genuinely wins.
+    const dragRank = zOrders[component.id] ?? 0;
     const groupZIndex = isBreadboard
       ? -1
-      : isSeated && occludesWhenSeated
-        ? isSelected
-          ? 37
-          : 36
-        : isSelected
-          ? 2
-          : 1;
+      : dragRank > 0
+        ? 10 + dragRank
+        : isSeated && occludesWhenSeated
+          ? isSelected
+            ? 37
+            : 36
+          : isSelected
+            ? 2
+            : 1;
 
     return (
       <React.Fragment key={component.id}>