diff --git a/frontend-modern/src/__tests__/useAppRuntimeState.test.ts b/frontend-modern/src/__tests__/useAppRuntimeState.test.ts
new file mode 100644
index 000000000..2e7e149ce
--- /dev/null
+++ b/frontend-modern/src/__tests__/useAppRuntimeState.test.ts
@@ -0,0 +1,277 @@
+import { createRoot } from 'solid-js';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+type UseAppRuntimeStateModule = typeof import('@/useAppRuntimeState');
+
+const flushAsync = async () => {
+  for (let i = 0; i < 8; i += 1) {
+    await Promise.resolve();
+  }
+};
+
+describe('useAppRuntimeState', () => {
+  let useAppRuntimeState: UseAppRuntimeStateModule['useAppRuntimeState'];
+  let apiFetchMock: ReturnType<typeof vi.fn>;
+  let orgsListMock: ReturnType<typeof vi.fn>;
+  let loadLicenseStatusMock: ReturnType<typeof vi.fn>;
+  let isMultiTenantEnabledMock: ReturnType<typeof vi.fn>;
+  let isHostedModeEnabledMock: ReturnType<typeof vi.fn>;
+  let getOrgIDMock: ReturnType<typeof vi.fn>;
+  let setOrgIDMock: ReturnType<typeof vi.fn>;
+  let showToastMock: ReturnType<typeof vi.fn>;
+
+  beforeEach(async () => {
+    vi.resetModules();
+
+    Object.defineProperty(window, 'matchMedia', {
+      writable: true,
+      configurable: true,
+      value: vi.fn().mockReturnValue({
+        matches: false,
+        media: '(prefers-color-scheme: dark)',
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+      }),
+    });
+
+    Object.defineProperty(window, 'requestIdleCallback', {
+      writable: true,
+      configurable: true,
+      value: vi.fn((cb: IdleRequestCallback) =>
+        window.setTimeout(() => cb({ didTimeout: false, timeRemaining: () => 50 } as IdleDeadline), 0),
+      ),
+    });
+
+    Object.defineProperty(window, 'cancelIdleCallback', {
+      writable: true,
+      configurable: true,
+      value: vi.fn((id: number) => window.clearTimeout(id)),
+    });
+
+    apiFetchMock = vi.fn(async (url: string) => {
+      if (url === '/api/security/status') {
+        return new Response(JSON.stringify({ hasAuthentication: true }), { status: 200 });
+      }
+      if (url === '/api/state') {
+        return new Response('{}', { status: 200 });
+      }
+      if (url === '/api/health') {
+        return new Response('{}', { status: 200 });
+      }
+      throw new Error(`Unhandled apiFetch URL: ${url}`);
+    });
+    orgsListMock = vi.fn().mockResolvedValue([{ id: 'acme', displayName: 'Acme' }]);
+    loadLicenseStatusMock = vi.fn().mockResolvedValue(undefined);
+    isMultiTenantEnabledMock = vi.fn().mockReturnValue(false);
+    isHostedModeEnabledMock = vi.fn().mockReturnValue(false);
+    getOrgIDMock = vi.fn().mockReturnValue('default');
+    setOrgIDMock = vi.fn();
+    showToastMock = vi.fn();
+
+    vi.doMock('@/stores/websocket-global', () => ({
+      getGlobalWebSocketStore: () => ({
+        state: {
+          connectedInfrastructure: [],
+          metrics: [],
+          performance: {
+            apiCallDuration: {},
+            lastPollDuration: 0,
+            pollingStartTime: '',
+            totalApiCalls: 0,
+            failedApiCalls: 0,
+            cacheHits: 0,
+            cacheMisses: 0,
+          },
+          connectionHealth: {},
+          stats: {
+            startTime: new Date().toISOString(),
+            uptime: 0,
+            pollingCycles: 0,
+            webSocketClients: 0,
+            version: '0.0.0',
+          },
+          activeAlerts: [],
+          recentlyResolved: [],
+          lastUpdate: 0,
+          resources: [],
+        },
+        connected: () => false,
+        reconnecting: () => false,
+        reconnect: vi.fn(),
+        switchUrl: vi.fn(),
+      }),
+    }));
+
+    vi.doMock('@/utils/logger', () => ({
+      logger: {
+        debug: vi.fn(),
+        info: vi.fn(),
+        warn: vi.fn(),
+        error: vi.fn(),
+      },
+    }));
+
+    vi.doMock('@/constants', () => ({
+      POLLING_INTERVALS: { DATA_FLASH: 50 },
+    }));
+
+    vi.doMock('@/utils/localStorage', () => ({
+      STORAGE_KEYS: {
+        AUTH: 'auth',
+        ORG_ID: 'org_id',
+        GUEST_METADATA: 'guest_metadata',
+        DOCKER_METADATA: 'docker_metadata',
+      },
+    }));
+
+    vi.doMock('@/api/orgs', () => ({
+      OrgsAPI: {
+        list: orgsListMock,
+      },
+    }));
+
+    vi.doMock('@/api/settings', () => ({
+      SettingsAPI: {
+        getSystemSettings: vi.fn().mockResolvedValue({ theme: '' }),
+        updateSystemSettings: vi.fn(),
+      },
+    }));
+
+    vi.doMock('@/utils/apiClient', () => ({
+      apiFetch: apiFetchMock,
+      getOrgID: getOrgIDMock,
+      setOrgID: setOrgIDMock,
+    }));
+
+    vi.doMock('@/stores/events', () => ({
+      eventBus: {
+        on: vi.fn(),
+        off: vi.fn(),
+        emit: vi.fn(),
+      },
+    }));
+
+    vi.doMock('@/utils/toast', () => ({
+      showToast: showToastMock,
+    }));
+
+    vi.doMock('@/stores/updates', () => ({
+      updateStore: {
+        versionInfo: vi.fn().mockReturnValue(null),
+        checkForUpdates: vi.fn().mockResolvedValue(undefined),
+      },
+    }));
+
+    vi.doMock('@/utils/infrastructureSummaryCache', () => ({
+      fetchInfrastructureSummaryAndCache: vi.fn().mockResolvedValue(undefined),
+      hasFreshInfrastructureSummaryCache: vi.fn().mockReturnValue(false),
+    }));
+
+    vi.doMock('@/routing/resourceLinks', () => ({
+      buildInfrastructurePath: () => '/infrastructure',
+    }));
+
+    vi.doMock('@/stores/metricsCollector', () => ({
+      startMetricsCollector: vi.fn(),
+    }));
+
+    vi.doMock('@/stores/alertsActivation', () => ({
+      useAlertsActivation: () => ({
+        refreshConfig: vi.fn().mockResolvedValue(undefined),
+        refreshActiveAlerts: vi.fn().mockResolvedValue(undefined),
+      }),
+    }));
+
+    vi.doMock('@/utils/theme', () => ({
+      applyThemeClass: vi.fn(),
+      computeIsDark: vi.fn().mockReturnValue(false),
+      getStoredThemePreference: vi.fn().mockReturnValue('system'),
+      hasStoredThemePreference: vi.fn().mockReturnValue(false),
+      normalizeThemePreference: vi.fn((value: string) => value),
+      persistThemePreference: vi.fn(),
+    }));
+
+    vi.doMock('@/utils/url', () => ({
+      initKioskMode: vi.fn(),
+      getPulseWebSocketUrl: vi.fn().mockReturnValue('ws://127.0.0.1/ws'),
+    }));
+
+    vi.doMock('@/hooks/useKioskMode', () => ({
+      syncKioskMode: vi.fn(),
+    }));
+
+    vi.doMock('@/stores/license', () => ({
+      isHostedModeEnabled: isHostedModeEnabledMock,
+      isMultiTenantEnabled: isMultiTenantEnabledMock,
+      licenseLoaded: vi.fn().mockReturnValue(true),
+      loadLicenseStatus: loadLicenseStatusMock,
+    }));
+
+    vi.doMock('@/utils/layout', () => ({
+      layoutStore: {
+        loadFromServer: vi.fn(),
+      },
+    }));
+
+    vi.doMock('@/stores/systemSettings', () => ({
+      markSystemSettingsLoadedWithDefaults: vi.fn(),
+      updateSystemSettingsFromResponse: vi.fn(),
+    }));
+
+    ({ useAppRuntimeState } = await import('@/useAppRuntimeState'));
+  });
+
+  afterEach(() => {
+    vi.clearAllMocks();
+    vi.resetModules();
+  });
+
+  const mountHook = () => {
+    let dispose = () => {};
+    let hookState: ReturnType<UseAppRuntimeStateModule['useAppRuntimeState']>;
+
+    createRoot((d) => {
+      dispose = d;
+      hookState = useAppRuntimeState();
+    });
+
+    return { dispose, hookState: hookState! };
+  };
+
+  it('stays on the default organization path when multi-tenant is not enabled', async () => {
+    isMultiTenantEnabledMock.mockReturnValue(false);
+    const { hookState, dispose } = mountHook();
+
+    await flushAsync();
+    await flushAsync();
+
+    expect(orgsListMock).not.toHaveBeenCalled();
+    expect(setOrgIDMock).toHaveBeenCalledWith('default');
+    expect(hookState.organizations()).toEqual([
+      { id: 'default', displayName: 'Default Organization' },
+    ]);
+    expect(hookState.activeOrgID()).toBe('default');
+    expect(showToastMock).not.toHaveBeenCalledWith(
+      'error',
+      'Failed to load organizations. Using default.',
+    );
+
+    dispose();
+  });
+
+  it('loads organizations from the org API when multi-tenant is enabled', async () => {
+    isMultiTenantEnabledMock.mockReturnValue(true);
+    getOrgIDMock.mockReturnValue('acme');
+    const { hookState, dispose } = mountHook();
+
+    await flushAsync();
+    await flushAsync();
+
+    expect(orgsListMock).toHaveBeenCalledOnce();
+    expect(setOrgIDMock).toHaveBeenCalledWith('acme');
+    expect(hookState.organizations()).toEqual([{ id: 'acme', displayName: 'Acme' }]);
+    expect(hookState.activeOrgID()).toBe('acme');
+
+    dispose();
+  });
+});