Unify UI workflows and streamline fleet management

tests/unit/ui-poll.test.ts

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+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import { pollVisible } from '../../src/lib/ui/poll.js';
+
+let documentStub: EventTarget & { visibilityState: string };
+let stop: (() => void) | undefined;
+beforeEach(() => {
+    vi.useFakeTimers();
+    documentStub = Object.assign(new EventTarget(), { visibilityState: 'visible' });
+    vi.stubGlobal('document', documentStub);
+});
+afterEach(() => { stop?.(); stop = undefined; vi.useRealTimers(); vi.unstubAllGlobals(); vi.restoreAllMocks(); });
+const visibility = (state: string) => { documentStub.visibilityState = state; documentStub.dispatchEvent(new Event('visibilitychange')); };
+
+describe('visible page polling', () => {
+    it('waits for a request to finish before scheduling the next request', async () => {
+        let finish!: () => void;
+        const task = vi.fn(() => new Promise<void>(resolve => { finish = resolve; }));
+        stop = pollVisible(task, 1000);
+        await vi.advanceTimersByTimeAsync(5000);
+        visibility('visible');
+        expect(task).toHaveBeenCalledTimes(1);
+        finish(); await vi.advanceTimersByTimeAsync(999);
+        expect(task).toHaveBeenCalledTimes(1);
+        await vi.advanceTimersByTimeAsync(1);
+        expect(task).toHaveBeenCalledTimes(2);
+    });
+    it('pauses when hidden and refreshes on return, including hiding during a request', async () => {
+        let finish!: () => void;
+        const task = vi.fn(() => new Promise<void>(resolve => { finish = resolve; }));
+        stop = pollVisible(task, 1000);
+        visibility('hidden'); finish();
+        await vi.advanceTimersByTimeAsync(5000);
+        expect(task).toHaveBeenCalledTimes(1);
+        visibility('visible');
+        expect(task).toHaveBeenCalledTimes(2);
+        finish(); stop();
+        visibility('visible'); await vi.advanceTimersByTimeAsync(5000);
+        expect(task).toHaveBeenCalledTimes(2);
+    });
+    it('recovers after a failed request and supports a delayed initial refresh', async () => {
+        vi.spyOn(console, 'error').mockImplementation(() => {});
+        const task = vi.fn().mockRejectedValueOnce(new Error('offline')).mockResolvedValue(undefined);
+        stop = pollVisible(task, 1000, false);
+        expect(task).not.toHaveBeenCalled();
+        await vi.advanceTimersByTimeAsync(2000);
+        expect(task).toHaveBeenCalledTimes(2);
+    });
+});