feat(core): add nodes option to fitView

# What's changed?

- Add `nodes` option to `fitView`
- Allows `fitView` to only fit around a certain set of specified nodeIds

packages/core/src/store/utils.ts

@@ -141,7 +141,11 @@ export function fitView(get: StoreApi<ReactFlowState>['getState'], options: Inte
 
   if ((options.initial && !fitViewOnInitDone && fitViewOnInit) || !options.initial) {
     if (d3Zoom && d3Selection) {
-      const nodes = getNodes().filter((n) => (options.includeHiddenNodes ? n.width && n.height : !n.hidden));
+      let nodes: Node[] = getNodes().filter((n) => (options.includeHiddenNodes ? n.width && n.height : !n.hidden));
+
+      if (options.nodes?.length) {
+        nodes = nodes.filter((n) => options.nodes?.includes(n.id))
+      }
 
       const nodesInitialized = nodes.every((n) => n.width && n.height);
 

packages/core/src/types/general.ts

@@ -76,6 +76,7 @@ export type FitViewOptions = {
   minZoom?: number;
   maxZoom?: number;
   duration?: number;
+  nodes?: string[];
 };
 
 export type OnConnectStartParams = {