feat: implement fresh device discovery and update UI for device refresh

internal/device/manager.go

@@ -232,7 +232,20 @@ func (manager *Manager) Discover(ctx context.Context) ([]Device, error) {
 		state.opMu.Unlock()
 	}
 	manager.resetChangedClients()
-	return manager.List(), nil
+
+	// List retains previously discovered devices so configured hardware can be
+	// rendered as offline after it is unplugged. Discover, however, is a fresh
+	// physical scan and must only return devices that are present now. Returning
+	// the retained entries here allowed an unplugged modem to be selected and
+	// added again from the device discovery screen.
+	devices := manager.List()
+	present := devices[:0]
+	for _, entry := range devices {
+		if entry.Discovered {
+			present = append(present, entry)
+		}
+	}
+	return present, nil
 }
 
 func (manager *Manager) resetChangedClients() {

internal/device/manager_test.go

@@ -45,6 +45,29 @@ func TestManagerDiscoversWiFiCallingOnlyReaderWithoutATPort(t *testing.T) {
 	}
 }
 
+func TestManagerDiscoverReturnsOnlyCurrentlyPresentDevices(t *testing.T) {
+	manager, id := newStartedTestManager(t, nil)
+	if devices := manager.List(); len(devices) != 1 || devices[0].ID != id || !devices[0].Discovered {
+		t.Fatalf("initial devices = %#v", devices)
+	}
+
+	manager.discoverer = staticDiscoverer{}
+	present, err := manager.Discover(context.Background())
+	if err != nil {
+		t.Fatalf("Discover after unplug: %v", err)
+	}
+	if len(present) != 0 {
+		t.Fatalf("present devices after unplug = %#v, want none", present)
+	}
+
+	// The retained entry is still available to the configured-device dashboard,
+	// but is explicitly offline and cannot be offered by fresh discovery.
+	retained := manager.List()
+	if len(retained) != 1 || retained[0].ID != id || retained[0].Discovered {
+		t.Fatalf("retained devices after unplug = %#v", retained)
+	}
+}
+
 func TestManagerRefreshBuildsEC20Snapshot(t *testing.T) {
 	client := &transcriptClient{steps: []clientStep{
 		{

internal/server/device_api.go

@@ -344,7 +344,14 @@ func (s *Server) handleDiscoveredDevices(w http.ResponseWriter, r *http.Request)
 		writeJSON(w, http.StatusOK, map[string]any{"data": map[string]any{"devices": []any{}}})
 		return true
 	}
-	devices := s.devices.List()
+	// This endpoint backs the add-device dialog. Always perform a new physical
+	// scan instead of serving Manager.List(), which intentionally retains
+	// unplugged configured devices so the main device list can show them offline.
+	devices, err := s.devices.Discover(r.Context())
+	if err != nil {
+		s.writeDeviceError(w, err)
+		return true
+	}
 	configured, err := s.store.ListDevices(r.Context())
 	if err != nil {
 		s.writeStoreError(w, err)
@@ -352,6 +359,9 @@ func (s *Server) handleDiscoveredDevices(w http.ResponseWriter, r *http.Request)
 	}
 	result := make([]map[string]any, 0, len(devices))
 	for _, entry := range devices {
+		if !entry.Discovered {
+			continue
+		}
 		candidate := entry.Candidate
 		atPorts := make([]string, 0, len(candidate.Ports))
 		for _, port := range candidate.Ports {

internal/server/device_discovery_api_test.go

@@ -0,0 +1,72 @@
+package server
+
+import (
+	"context"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"vocat/internal/device"
+	"vocat/internal/modem"
+	"vocat/internal/store"
+)
+
+type discoverySnapshotController struct {
+	fakeDeviceController
+	entries       []device.Device
+	discoverCalls int
+}
+
+func (controller *discoverySnapshotController) Discover(context.Context) ([]device.Device, error) {
+	controller.discoverCalls++
+	return append([]device.Device(nil), controller.entries...), nil
+}
+
+func TestDiscoveredDevicesPerformsFreshScanAndOmitsAbsentEntries(t *testing.T) {
+	database, err := store.Open(context.Background(), ":memory:")
+	if err != nil {
+		t.Fatalf("store.Open: %v", err)
+	}
+	t.Cleanup(func() { _ = database.Close() })
+
+	controller := &discoverySnapshotController{
+		fakeDeviceController: fakeDeviceController{entry: device.Device{
+			ID: "stale-device", Discovered: false,
+			Candidate: modem.Candidate{ID: "stale-device", USBPath: "1-1"},
+		}},
+		entries: []device.Device{
+			{
+				ID: "current-device", Discovered: true,
+				Candidate: modem.Candidate{ID: "current-device", USBPath: "2-1"},
+			},
+			{
+				ID: "absent-device", Discovered: false,
+				Candidate: modem.Candidate{ID: "absent-device", USBPath: "3-1"},
+			},
+		},
+	}
+	server := &Server{
+		store: database, logger: regionTestLogger(),
+		maxRequestBodyBytes: 4096, devices: controller,
+	}
+	request := httptest.NewRequest(http.MethodGet, "/api/devices/discovered", nil)
+	recorder := httptest.NewRecorder()
+
+	if !server.handleDiscoveredDevices(recorder, request) {
+		t.Fatal("handleDiscoveredDevices returned false")
+	}
+	if recorder.Code != http.StatusOK {
+		t.Fatalf("status = %d, body = %s", recorder.Code, recorder.Body.String())
+	}
+	if controller.discoverCalls != 1 {
+		t.Fatalf("Discover calls = %d, want 1", controller.discoverCalls)
+	}
+	body := recorder.Body.String()
+	if !strings.Contains(body, "current-device") {
+		t.Fatalf("response omits current device: %s", body)
+	}
+	if strings.Contains(body, "stale-device") || strings.Contains(body, "absent-device") {
+		t.Fatalf("response contains an absent device: %s", body)
+	}
+}

web/src/components/devices/DeviceAddDialog.tsx

@@ -1,5 +1,5 @@
 import { useEffect, type ReactNode } from "react";
-import { SaveRegular } from "@fluentui/react-icons";
+import { ArrowSyncRegular, SaveRegular } from "@fluentui/react-icons";
 import { cx } from "../../lib/utils";
 import { Button, Input, Modal, Select, Spinner, Tag } from "../ui";
 import { isQmiControl } from "./shared";
@@ -17,6 +17,7 @@ export interface DeviceAddDialogProps {
   addConfig: AddDeviceForm;
   addSaving: boolean;
   onClose: () => void;
+  onRefresh: () => void;
   onSelectDevice: (d: DiscoveredDevice) => void;
   onConfigChange: (next: AddDeviceForm) => void;
   onSave: () => void;
@@ -85,7 +86,12 @@ export function DeviceAddDialog(props: DeviceAddDialogProps) {
         </div>
       }
     >
-      <div className="mb-3 text-sm text-gray-500">{t("选择一个“未配置”的设备，系统将自动填充 AT 端口与识别信息。")}</div>
+      <div className="mb-3 flex items-center justify-between gap-3">
+        <div className="text-sm text-gray-500">{t("选择一个“未配置”的设备，系统将自动填充 AT 端口与识别信息。")}</div>
+        <Button size="small" loading={props.discovering} onClick={props.onRefresh} icon={<ArrowSyncRegular />}>
+          {t("刷新设备")}
+        </Button>
+      </div>
       <div className="max-h-[260px] space-y-2 overflow-auto pr-1">
         {props.discovering ? (
           <div className="flex flex-col items-center justify-center py-10 text-gray-400">

web/src/lib/i18n-en.ts

@@ -993,6 +993,7 @@ export const EN_DICT: Record<string, string> = {
   最新: "Latest",
   加载更多: "Load More",
   刷新: "Refresh",
+  "刷新设备": "Refresh Devices",
 
   // ---- 代理 / 国家规则（i18n 补充） ----
   "绑定:": "Bound:",

web/src/pages/DevicesPage.tsx

@@ -136,11 +136,17 @@ export default function DevicesPage() {
 
   const loadDiscovered = useCallback(async () => {
     setDiscovering(true);
+    // Never leave a previous physical scan visible while a new scan is in
+    // progress or after it fails.
+    setDiscovered([]);
+    setAddSelected(null);
+    setAddConfig(EMPTY_ADD);
     try {
       const res = await api<{ devices?: DiscoveredDevice[] }>("/devices/discovered?with_imei=1");
-      setDiscovered(Array.isArray(res?.devices) ? res!.devices! : []);
+      const devices = Array.isArray(res?.devices) ? res!.devices! : [];
+      setDiscovered(devices);
     } catch {
-      /* ignore */
+      setDiscovered([]);
     } finally {
       setDiscovering(false);
     }
@@ -296,13 +302,13 @@ export default function DevicesPage() {
     try {
       await api("/devices/actions/rescan", { method: "POST" });
       message.success(t("设备重新扫描完成"));
-      await loadDevices(true);
+      await Promise.all([loadDevices(true), loadDiscovered()]);
     } catch (e) {
       message.error(apiMessage(e) || t("重新扫描失败"));
     } finally {
       setRescanning(false);
     }
-  }, [loadDevices]);
+  }, [loadDevices, loadDiscovered]);
 
   const handleOpenSms = useCallback(() => {
     const id = selectedIdRef.current;
@@ -736,6 +742,7 @@ export default function DevicesPage() {
         addConfig={addConfig}
         addSaving={addSaving}
         onClose={() => setAddOpen(false)}
+        onRefresh={() => void loadDiscovered()}
         onSelectDevice={selectDiscovered}
         onConfigChange={setAddConfig}
         onSave={saveAdd}