新增 POST /api/admin/notices、PATCH /api/admin/notices/{id}

保留超级管理员权限边界
支持草稿、发布、置顶、自动摘要
HTML 净化，拦截脚本和危险链接
公告更新与审计日志同事务提交
新增开关 ADMIN_NATIVE_NOTICE_WRITES_ENABLED=false
管理端公告列表和系统自动公告暂时仍由 Node 处理

tests/Eis.Infrastructure.Tests/Administration/AdminMigrationOptionsTests.cs

@@ -122,18 +122,35 @@ public sealed class AdminMigrationOptionsTests
         }, configurationEnabled: "true");
     }
 
+    [Fact]
+    public void EnablesNoticeWritesWithReadsAndSharedSessions()
+    {
+        WithEnvironment("true", null, null, () =>
+        {
+            var options = AdminMigrationOptions.FromEnvironment(
+                configuredNativeReadsEnabled: false,
+                authenticationNativeEnabled: true,
+                sharesLegacySessions: true);
+
+            Assert.True(options.NativeReadsEnabled);
+            Assert.True(options.NativeNoticeWritesEnabled);
+        }, noticeWritesEnabled: "true");
+    }
+
     private static void WithEnvironment(
         string? nativeReadsEnabled,
         string? nativeOrganizationWritesEnabled,
         string? allowMemory,
         Action test,
         string? accountBatchesEnabled = null,
-        string? configurationEnabled = null)
+        string? configurationEnabled = null,
+        string? noticeWritesEnabled = null)
     {
         var previousNativeReadsEnabled = Environment.GetEnvironmentVariable("ADMIN_NATIVE_READS_ENABLED");
         var previousNativeOrganizationWritesEnabled = Environment.GetEnvironmentVariable("ADMIN_NATIVE_ORGANIZATION_WRITES_ENABLED");
         var previousAccountBatchesEnabled = Environment.GetEnvironmentVariable("ADMIN_NATIVE_ACCOUNT_BATCHES_ENABLED");
         var previousConfigurationEnabled = Environment.GetEnvironmentVariable("ADMIN_NATIVE_CONFIGURATION_ENABLED");
+        var previousNoticeWritesEnabled = Environment.GetEnvironmentVariable("ADMIN_NATIVE_NOTICE_WRITES_ENABLED");
         var previousAllowMemory = Environment.GetEnvironmentVariable("ADMIN_NATIVE_ALLOW_MEMORY");
         try
         {
@@ -141,6 +158,7 @@ public sealed class AdminMigrationOptionsTests
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ORGANIZATION_WRITES_ENABLED", nativeOrganizationWritesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ACCOUNT_BATCHES_ENABLED", accountBatchesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_CONFIGURATION_ENABLED", configurationEnabled);
+            Environment.SetEnvironmentVariable("ADMIN_NATIVE_NOTICE_WRITES_ENABLED", noticeWritesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ALLOW_MEMORY", allowMemory);
             test();
         }
@@ -150,6 +168,7 @@ public sealed class AdminMigrationOptionsTests
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ORGANIZATION_WRITES_ENABLED", previousNativeOrganizationWritesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ACCOUNT_BATCHES_ENABLED", previousAccountBatchesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_CONFIGURATION_ENABLED", previousConfigurationEnabled);
+            Environment.SetEnvironmentVariable("ADMIN_NATIVE_NOTICE_WRITES_ENABLED", previousNoticeWritesEnabled);
             Environment.SetEnvironmentVariable("ADMIN_NATIVE_ALLOW_MEMORY", previousAllowMemory);
         }
     }

tests/Eis.Infrastructure.Tests/Public/NoticeContentFormatterTests.cs

@@ -33,6 +33,16 @@ public sealed class NoticeContentFormatterTests
         Assert.Contains("rel=\"noopener noreferrer\"", result, StringComparison.Ordinal);
     }
 
+    [Fact]
+    public void PlainText_PreservesBlockBoundariesAndDecodesEntities()
+    {
+        const string source = "<p>第一段&nbsp;内容</p><ul><li>第二项</li></ul>";
+
+        var result = _formatter.PlainText(source);
+
+        Assert.Equal("第一段 内容 第二项", result);
+    }
+
     [Fact]
     public void ContentHtml_ConvertsPlainTextParagraphsWithoutTrustingMarkup()
     {