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/manifest.json

@@ -0,0 +1,16 @@
+{
+  "id": "fusion-plugin-dependency-graph",
+  "name": "Dependency Graph",
+  "version": "0.1.0",
+  "description": "Top-level dependency graph dashboard view",
+  "dashboardViews": [
+    {
+      "viewId": "graph",
+      "label": "Graph",
+      "componentPath": "./src/DependencyGraphView.tsx",
+      "icon": "Network",
+      "placement": "more",
+      "order": 40
+    }
+  ]
+}