feat(FN-3903): merge duplicate createRouteContext mock in plugin-routes tes

Cleans up a duplicate `createRouteContext` mock in the plugin-routes test file, reducing 9 lines of dead code.

Fusion-Task-Id: FN-3903

packages/dashboard/src/__tests__/plugin-routes.test.ts

@@ -119,15 +119,6 @@ function createMockPluginLoader(overrides: Partial<PluginLoader> = {}): PluginLo
     stopAllPlugins: vi.fn().mockResolvedValue(undefined),
     invokeHook: vi.fn().mockResolvedValue(undefined),
     reloadPlugin: vi.fn().mockResolvedValue(undefined),
-    createRouteContext: vi.fn().mockImplementation(async (pluginId: string, ctx: Record<string, unknown>) => ({
-      pluginId,
-      taskStore: ctx.taskStore,
-      settings: ctx.settings ?? {},
-      logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn(), debug: vi.fn() },
-      emitEvent: vi.fn(),
-      createAiSession: await fusionCore.getCreateAiSessionFactory(),
-      resolveProjectTaskStore: ctx.resolveProjectTaskStore,
-    })),
     ...overrides,
   } as unknown as PluginLoader;
 }