refactor!: rename the project from Monitor to MoShiro [CI]

Namespaces, assemblies, solution, binaries, images, systemd units, config paths, environment variables, protocol methods and the Linux user are all renamed. Breaking: existing databases, node identities and installed units must be recreated.

backend/src/MoShiro.Backend/HttpGeoLookup.cs

@@ -0,0 +1,73 @@
+using System.Text.Json;
+using MoShiro.Backend.Application;
+
+namespace MoShiro.Backend;
+
+/// <summary>
+/// 用 IP 归属查询服务（<c>GET {地址}/lookup?ip=…</c>）查国家和运营商。
+/// 失败（超时、网络不通、服务返回错误）一律返回 null，不往外抛：展示信息没有也不影响别的功能。
+/// </summary>
+public sealed class HttpGeoLookup : IGeoLookup, IDisposable
+{
+    private readonly HttpClient _http;
+
+    public HttpGeoLookup(string baseUrl)
+    {
+        _http = new HttpClient { BaseAddress = new Uri(baseUrl.TrimEnd('/') + "/"), Timeout = TimeSpan.FromSeconds(6) };
+        _http.DefaultRequestHeaders.UserAgent.ParseAdd("MoShiro");
+    }
+
+    public async ValueTask<GeoInfo?> LookupAsync(string host, CancellationToken ct)
+    {
+        try
+        {
+            using HttpResponseMessage response = await _http.GetAsync("lookup?ip=" + Uri.EscapeDataString(host), ct);
+            if (!response.IsSuccessStatusCode)
+            {
+                return null;
+            }
+
+            using JsonDocument doc = await JsonDocument.ParseAsync(await response.Content.ReadAsStreamAsync(ct), cancellationToken: ct);
+            return Parse(doc.RootElement);
+        }
+        catch (Exception ex) when (ex is HttpRequestException or TaskCanceledException or JsonException or InvalidOperationException)
+        {
+            return null;
+        }
+    }
+
+    /// <summary>只取国家代码、ASN、组织名；其余字段（城市、经纬度、网段……）一概不读。</summary>
+    public static GeoInfo? Parse(JsonElement root)
+    {
+        if (root.TryGetProperty("found", out JsonElement found) && found.ValueKind == JsonValueKind.False)
+        {
+            return null;
+        }
+
+        bool isPrivate = root.TryGetProperty("is_private", out JsonElement priv) && priv.ValueKind == JsonValueKind.True;
+        string? country = root.TryGetProperty("country_region", out JsonElement region) && region.TryGetProperty("iso_code", out JsonElement code) && code.ValueKind == JsonValueKind.String ? code.GetString() : null;
+        int? asn = null;
+        string? organization = null;
+        if (root.TryGetProperty("network", out JsonElement network))
+        {
+            if (network.TryGetProperty("asn", out JsonElement asnValue) && asnValue.TryGetInt32(out int number))
+            {
+                asn = number;
+            }
+
+            string? isp = network.TryGetProperty("isp", out JsonElement ispValue) && ispValue.ValueKind == JsonValueKind.String ? ispValue.GetString() : null;
+            string? org = network.TryGetProperty("organization", out JsonElement orgValue) && orgValue.ValueKind == JsonValueKind.String ? orgValue.GetString() : null;
+            organization = string.IsNullOrWhiteSpace(isp) ? org : isp;
+        }
+
+        return new GeoInfo(country, asn, organization, isPrivate);
+    }
+
+    public void Dispose() => _http.Dispose();
+}
+
+/// <summary>不查（<c>MoShiro__GeoLookupUrl</c> 留空）。</summary>
+public sealed class NoGeoLookup : IGeoLookup
+{
+    public ValueTask<GeoInfo?> LookupAsync(string host, CancellationToken ct) => ValueTask.FromResult<GeoInfo?>(null);
+}