feat: add Zustand store for managing flow view side panel state

Author: nicosammito

src/packages/ce/src/flow/hooks/Flow.view.hook.ts

@@ -0,0 +1,18 @@
+import {create} from "zustand"
+
+/**
+ * Shared state for the flow view side panels (file / execution). Lifting this out of
+ * the page component lets deeply nested components (e.g. the definition panel dialog)
+ * open a specific panel without prop drilling.
+ */
+interface FlowViewState {
+    tab?: string
+    setTab: (tab?: string) => void
+    toggleTab: (tab: string) => void
+}
+
+export const useFlowViewStore = create<FlowViewState>((setState) => ({
+    tab: undefined,
+    setTab: (tab) => setState({tab}),
+    toggleTab: (tab) => setState((state) => ({tab: state.tab === tab ? undefined : tab})),
+}))