feat.在线安装器，更好的Issue与pull request模板。

LanMountainDesktop.Shared.Contracts/Privacy/IPrivacyDeviceIdentityProvider.cs

@@ -0,0 +1,6 @@
+namespace LanMountainDesktop.Shared.Contracts.Privacy;
+
+public interface IPrivacyDeviceIdentityProvider
+{
+    string GetOrCreateDeviceId();
+}

LanMountainDesktop.Shared.Contracts/Privacy/PrivacyDeviceIdentityProvider.cs

@@ -0,0 +1,105 @@
+using System.Security.Cryptography;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace LanMountainDesktop.Shared.Contracts.Privacy;
+
+public sealed partial class PrivacyDeviceIdentityProvider : IPrivacyDeviceIdentityProvider
+{
+    public const string DefaultIdentityFileName = "privacy-device.identity.json";
+
+    private readonly string _identityPath;
+    private readonly object _gate = new();
+
+    public PrivacyDeviceIdentityProvider(string? identityPath = null)
+    {
+        _identityPath = string.IsNullOrWhiteSpace(identityPath)
+            ? GetDefaultIdentityPath()
+            : Path.GetFullPath(identityPath);
+    }
+
+    public string GetOrCreateDeviceId()
+    {
+        lock (_gate)
+        {
+            var existing = TryLoad();
+            if (!string.IsNullOrWhiteSpace(existing?.DeviceId))
+            {
+                return existing.DeviceId;
+            }
+
+            var created = new PrivacyDeviceIdentityDocument(
+                SchemaVersion: 1,
+                DeviceId: GenerateDeviceId(),
+                CreatedAtUtc: DateTimeOffset.UtcNow);
+            Save(created);
+            return created.DeviceId;
+        }
+    }
+
+    public static string GetDefaultIdentityPath()
+    {
+        var root = Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData);
+        if (string.IsNullOrWhiteSpace(root))
+        {
+            root = AppContext.BaseDirectory;
+        }
+
+        return Path.Combine(root, "LanMountainDesktop", DefaultIdentityFileName);
+    }
+
+    private PrivacyDeviceIdentityDocument? TryLoad()
+    {
+        try
+        {
+            if (!File.Exists(_identityPath))
+            {
+                return null;
+            }
+
+            var json = File.ReadAllText(_identityPath);
+            return JsonSerializer.Deserialize(
+                json,
+                PrivacyDeviceIdentityJsonContext.Default.PrivacyDeviceIdentityDocument);
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    private void Save(PrivacyDeviceIdentityDocument document)
+    {
+        var directory = Path.GetDirectoryName(_identityPath);
+        if (!string.IsNullOrWhiteSpace(directory))
+        {
+            Directory.CreateDirectory(directory);
+        }
+
+        var tempPath = $"{_identityPath}.{Guid.NewGuid():N}.tmp";
+        var json = JsonSerializer.Serialize(
+            document,
+            PrivacyDeviceIdentityJsonContext.Default.PrivacyDeviceIdentityDocument);
+        File.WriteAllText(tempPath, json);
+        File.Move(tempPath, _identityPath, overwrite: true);
+    }
+
+    private static string GenerateDeviceId()
+    {
+        Span<byte> bytes = stackalloc byte[32];
+        RandomNumberGenerator.Fill(bytes);
+        return Convert.ToHexString(bytes).ToLowerInvariant();
+    }
+
+    private sealed record PrivacyDeviceIdentityDocument(
+        int SchemaVersion,
+        string DeviceId,
+        DateTimeOffset CreatedAtUtc);
+
+    [JsonSourceGenerationOptions(
+        PropertyNamingPolicy = JsonKnownNamingPolicy.CamelCase,
+        WriteIndented = true,
+        DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull)]
+    [JsonSerializable(typeof(PrivacyDeviceIdentityDocument))]
+    private sealed partial class PrivacyDeviceIdentityJsonContext : JsonSerializerContext;
+}