Add shifting of layers in stacks as blocks that collide and bump other layers/nodes (#1940)

* Shift nodes as blocks

* Implement rubber banding

* Improve upstream locking when shifting layers

* WIP: Reworked shifting

* WIP: Reworked node shifting

* Finish shifting

* Fix demo artwork

* Code review

* Right click to end shift

* Improve rubber banding

* Fix clippy issues

* Skip collision for intersecting nodes

* Rubber banding bug fix

* Fix ctrl+delete node in chain

* Grip drag

* Fix layer width

* Add icon to frontend for the solo drag grip

* Reconnect during ctrl+delete

* Code review

---------

Co-authored-by: Keavon Chambers <keavon@keavon.com>

frontend/src/components/views/Graph.svelte

@@ -456,7 +456,7 @@
 				{#each $nodeGraph.clickTargets.portClickTargets as pathString}
 					<path class="port" d={pathString} />
 				{/each}
-				{#each $nodeGraph.clickTargets.visibilityClickTargets as pathString}
+				{#each $nodeGraph.clickTargets.iconClickTargets as pathString}
 					<path class="visibility" d={pathString} />
 				{/each}
 				<path class="all-nodes-bounding-box" d={$nodeGraph.clickTargets.allNodesBoundingBox} />
@@ -642,6 +642,7 @@
 						{node.displayName}
 					</span>
 				</div>
+				<div class="solo-drag-grip" title="Drag only this layer without pushing others outside the stack"></div>
 				<IconButton
 					class={"visibility"}
 					data-visibility-button
@@ -1238,6 +1239,23 @@
 				}
 			}
 
+			.solo-drag-grip {
+				width: 8px;
+				height: 24px;
+				background-position: 2px 8px;
+				right: calc(-12px + 24px);
+				border-radius: 2px;
+			}
+
+			.solo-drag-grip:hover,
+			&.selected .solo-drag-grip {
+				background-image: var(--icon-drag-grip);
+
+				&:hover {
+					background-image: var(--icon-drag-grip-hover);
+				}
+			}
+
 			.visibility {
 				position: absolute;
 				right: -12px;
@@ -1247,6 +1265,7 @@
 				left: calc(-3px + var(--node-chain-area-left-extension) * 24px - 36px);
 			}
 
+			.solo-drag-grip,
 			.visibility,
 			.input.ports,
 			.input.ports .port {