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/fleet/src/Fleet.Server.Abstractions/ServerContracts.cs

@@ -19,6 +19,21 @@ public interface IServerIdentity
 }
 
 /// <summary>操作员集合的链（passkey 签的，创世在前）。没有初始化信任根时是空的。节点注册时用它确认「这个面板确实是我的操作员的」。</summary>
+/// <summary>节点握手时自述的二进制（旧节点没有）。</summary>
+public sealed record BinaryEvidence(string? Sha256, string? Manifest, string? Signature);
+
+/// <summary>是否让这个节点继续：不放行时 <c>Reason</c> 会原样告诉节点（这是它自己的信息，不是秘密）。</summary>
+public sealed record BinaryDecision(bool Accept, string Reason = "");
+
+/// <summary>
+/// 服务端对节点二进制的把关：节点第一次握手成功的那一刻绑定它的二进制哈希，之后哈希对不上、又不在 CI 签名的更新清单里，就不让它继续运行。
+/// 没有注册实现时不做任何检查。
+/// </summary>
+public interface IBinaryAttestor
+{
+    ValueTask<BinaryDecision> CheckAsync(NodeRecord node, BinaryEvidence evidence, CancellationToken ct);
+}
+
 public interface IOperatorTrustSource
 {
     ValueTask<IReadOnlyList<SignedStatementDto>> ChainAsync(CancellationToken ct);