feat(FN-3079): add plugin dashboard views and dependency graph plugin

- Add plugin dashboard view registration and hosting across core, dashboard routes, and plugin SDK exports
- Integrate plugin-provided views into app navigation, mobile/header UI, and view state hooks with coverage
- Add fusion-plugin-dependency-graph example plugin with persisted storage, dashboard view UI, and manifest wiring
- Update plugin authoring and architecture docs for dashboard view extension points
- Add a changeset for @runfusion/fusion covering plugin dashboard view support

Fusion-Task-Id: FN-3079

plugins/fusion-plugin-dependency-graph/src/index.ts

@@ -0,0 +1,25 @@
+import { definePlugin } from "@fusion/plugin-sdk";
+
+const plugin = definePlugin({
+  manifest: {
+    id: "fusion-plugin-dependency-graph",
+    name: "Dependency Graph",
+    version: "0.1.0",
+    description: "Top-level dependency graph dashboard view",
+  },
+  state: "installed",
+  hooks: {},
+  dashboardViews: [
+    {
+      viewId: "graph",
+      label: "Graph",
+      componentPath: "./src/DependencyGraphView.tsx",
+      icon: "Network",
+      placement: "more",
+      order: 40,
+    },
+  ],
+});
+
+export default plugin;
+export { DependencyGraphView } from "./DependencyGraphView";