feat: bind each node to the binary it runs at its first handshake; refuse changes that are not in a CI-signed manifest [CI]

backend/src/MoShiro.Backend.Api/Contracts/AdminDtos.cs

@@ -178,7 +178,10 @@ public sealed record ChangePasswordRequest(string Password);
 public sealed record RecomputeDto(string State, IReadOnlyList<string> Metrics, long WindowsDone, long WindowsTotal, DateTimeOffset? From, DateTimeOffset? To, int QueueLength);
 
 /// <summary>管理端看的构建信息：每个节点自报的版本、tag、提交和构建时间，以及系统。</summary>
-public sealed record NodeBuildDto(string Id, string Kind, string? Os, string? OsName, string? Arch, string? Version, string? Tag, string? Commit, string? BuiltAt, NodeUpdateDto? Update = null);
+/// <summary>节点二进制的绑定：第一次握手成功时绑定的 SHA-256。<c>Signed</c> 表示它出现在一份 CI 签名的清单里（否则只是首次握手时记下的）；<c>Violation</c> 是最近一次不符的原因，下一次握手符合了就清掉。</summary>
+public sealed record NodeBinaryDto(string Sha256, bool Signed, long Seq, DateTimeOffset BoundAt, string? Violation, DateTimeOffset? ViolationAt);
+
+public sealed record NodeBuildDto(string Id, string Kind, string? Os, string? OsName, string? Arch, string? Version, string? Tag, string? Commit, string? BuiltAt, NodeUpdateDto? Update = null, NodeBinaryDto? Binary = null);
 
 /// <summary>节点宿主机上的更新器报告的状态（<c>up_to_date</c>、<c>available</c>、<c>applying</c>、<c>failed</c>、<c>rolled_back</c>、<c>invalid</c>）；没装更新器的节点没有这个字段。</summary>
 public sealed record NodeUpdateDto(string State, string? CurrentDigest, string? AvailableTag, string? AvailableVersion, string? Error, DateTimeOffset? At);