fix: close plugin workspace acceptance gaps

tests/unit/plugin-workspace-query.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, it } from 'vitest';
 import {
   parsePluginWorkspaceSearch,
+  resolvePluginWorkspaceSearch,
   serializePluginWorkspaceSearch,
 } from '@/pages/Plugins/plugin-workspace-query';
 
@@ -22,6 +23,30 @@ describe('plugin workspace URL state', () => {
     expect(parsePluginWorkspaceSearch(new URLSearchParams('scope=project'), false).scope).toBe('all');
   });
 
+  it('reports a project-scope fallback while returning the exact canonical URL state', () => {
+    const fallback = resolvePluginWorkspaceSearch(
+      new URLSearchParams('scope=project&source=remote&state=broken'),
+      false,
+    );
+
+    expect(fallback).toEqual({
+      filters: {
+        scope: 'all', source: 'all', state: 'all', search: '', selectedKey: null,
+      },
+      canonicalSearch: 'scope=all&source=all&state=all',
+      scopeFallback: true,
+    });
+
+    const afterProjectAppears = resolvePluginWorkspaceSearch(new URLSearchParams(), true);
+    expect(afterProjectAppears).toEqual({
+      filters: {
+        scope: 'project', source: 'all', state: 'all', search: '', selectedKey: null,
+      },
+      canonicalSearch: 'scope=project&source=all&state=all',
+      scopeFallback: false,
+    });
+  });
+
   it('round-trips canonical filters and source-qualified selection', () => {
     const serialized = serializePluginWorkspaceSearch({
       scope: 'all',