fix: GotifyApiService 改为绝对 URI + 实时重读 URL/Token

修复 bug:用户改完 Gotify URL 后,历史 API 仍然请求老地址(127.0.0.1:8080)。

根因:HttpClient.BaseAddress 在构造后只读,GotifyApiService 在构造函数里把 _config.Gotify.Url 写进 BaseAddress 后就不再更新,而用户通过主窗改 URL 只是改了 in-memory _config 对象,不会重建 HttpClient。

修法:
- HttpClient 不再设 BaseAddress,所有请求走绝对 URI(BuildUri 每次从 _config 重新组装)
- 加 SyncAuthHeaders 方法,URL 或 Token 变了就重置 DefaultRequestHeaders.Authorization
- _config 字段类型从 GotifyConfig 改成 AppConfig,这样能读到完整引用,GetRecentMessagesAsync 之类的才会用新值

现在点「保存并重连」后,刷历史/WebSocket/通知 全部会用新 URL,不用重启 app。

验证:日志里看到从 127.0.0.1:8080 → kennethcheng.cc:50334,401 是 server 端 token 不认(下一步核对 Gotify 后台 Client Token)。

Services/GotifyApiService.cs

@@ -7,22 +7,55 @@ namespace WindowsGotify.Services;
 
 public sealed class GotifyApiService
 {
-    private readonly GotifyConfig _config;
+    private readonly AppConfig _config;
     private readonly Logger _logger;
     private readonly HttpClient _httpClient;
+    private readonly object _httpLock = new();
+    private string _appliedBaseUrl = "";
+    private string _appliedToken = "";
 
     public GotifyApiService(AppConfig config, Logger logger)
     {
-        _config = config.Gotify;
+        _config = config;
         _logger = logger;
         _httpClient = new HttpClient
         {
-            BaseAddress = new Uri(_config.Url.TrimEnd('/') + "/"),
             Timeout = TimeSpan.FromSeconds(15)
         };
+        SyncAuthHeaders();
+    }
 
-        _httpClient.DefaultRequestHeaders.Authorization =
+    /// <summary>
-            new AuthenticationHeaderValue("Bearer", _config.ClientToken);
+    /// 检测 URL/Token 是否变了,变了就刷新 HttpClient 的 Authorization。
+    /// 注意:HttpClient.BaseAddress 构造后只读,所以我们用绝对 URI 绕过。
+    /// </summary>
+    private void SyncAuthHeaders()
+    {
+        var baseUrl = (_config.Gotify.Url ?? "").TrimEnd('/');
+        var token = _config.Gotify.ClientToken ?? "";
+
+        if (_appliedBaseUrl == baseUrl && _appliedToken == token)
+            return;
+
+        lock (_httpLock)
+        {
+            if (_appliedBaseUrl == baseUrl && _appliedToken == token)
+                return;
+
+            // 显式给默认 header;实际请求走绝对 URI,所以 BaseAddress 永远为空
+            _httpClient.DefaultRequestHeaders.Authorization =
+                string.IsNullOrEmpty(token) ? null : new AuthenticationHeaderValue("Bearer", token);
+            _appliedBaseUrl = baseUrl;
+            _appliedToken = token;
+        }
+    }
+
+    private Uri BuildUri(string path)
+    {
+        var baseUrl = (_config.Gotify.Url ?? "").TrimEnd('/');
+        if (string.IsNullOrEmpty(baseUrl))
+            throw new InvalidOperationException("Gotify URL 未配置。请在主窗填入 URL 并保存。");
+        return new Uri(baseUrl + "/" + path);
     }
 
     /// <summary>
@@ -30,8 +63,9 @@ public sealed class GotifyApiService
     /// </summary>
     public async Task<List<GotifyMessage>> GetMessagesSinceAsync(long sinceId, int limit, CancellationToken ct)
     {
+        SyncAuthHeaders();
         var path = $"message?limit={Math.Clamp(limit, 1, 100)}&since={Math.Max(0, sinceId)}";
-        using var response = await _httpClient.GetAsync(path, ct);
+        using var response = await _httpClient.GetAsync(BuildUri(path), ct);
         response.EnsureSuccessStatusCode();
 
         await using var stream = await response.Content.ReadAsStreamAsync(ct);
@@ -44,8 +78,9 @@ public sealed class GotifyApiService
     /// </summary>
     public async Task<List<GotifyMessage>> GetRecentMessagesAsync(int limit, CancellationToken ct)
     {
+        SyncAuthHeaders();
         var path = $"message?limit={Math.Clamp(limit, 1, 100)}&since=0";
-        using var response = await _httpClient.GetAsync(path, ct);
+        using var response = await _httpClient.GetAsync(BuildUri(path), ct);
         response.EnsureSuccessStatusCode();
 
         await using var stream = await response.Content.ReadAsStreamAsync(ct);