chore: initial project import

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

@@ -0,0 +1,65 @@
+using System.Text.Json;
+using Fleet.Core;
+using Fleet.Rpc;
+
+namespace Fleet.Server;
+
+public sealed record EnrollmentContext(string? RemoteIp, JsonElement? ProductMeta);
+
+/// <summary>产品挂钩：节点注册成功之后调用。</summary>
+public interface IEnrollmentHook
+{
+    ValueTask OnEnrolledAsync(NodeRecord node, EnrollmentContext context, CancellationToken ct);
+}
+
+public enum NodeEventKind
+{
+    Online,
+    Offline,
+    Hello,
+    Heartbeat,
+}
+
+public sealed record NodeEvent(NodeEventKind Kind, NodeRecord Node, long AtMs, HelloParams? Hello = null, JsonElement? Extra = null);
+
+public interface INodeEventSink
+{
+    ValueTask OnEventAsync(NodeEvent nodeEvent, CancellationToken ct);
+}
+
+/// <summary>期望状态提供者：为每个节点计算期望状态的完整快照（天然幂等）。</summary>
+public interface IStateProvider
+{
+    /// <summary>状态文档类型，例如 <c>task_set</c>。</summary>
+    string Type { get; }
+
+    ValueTask<StateDocument?> GetAsync(NodeRecord node, CancellationToken ct);
+
+    /// <summary>节点应用之后回调，<c>rejected[]</c> 带结构化原因。</summary>
+    ValueTask OnAppliedAsync(NodeRecord node, long version, StateSyncResult result, CancellationToken ct);
+}
+
+public sealed record StateDocument(long Version, JsonElement Doc);
+
+public enum InboxOutcome
+{
+    Stored,
+    Duplicate,
+    Rejected,
+}
+
+/// <summary>收件箱：持久化之后才返回 Stored，框架随后才回复 ACK。</summary>
+public interface IInbox
+{
+    byte Channel { get; }
+
+    ValueTask<InboxOutcome> HandleAsync(NodeRecord node, Guid msgId, ReadOnlyMemory<byte> payload, CancellationToken ct);
+}
+
+/// <summary>通知 Fleet：某个节点的期望状态变了，需要重新计算并推送。</summary>
+public interface IStateNotifier
+{
+    void NotifyChanged(NodeId node);
+
+    void NotifyAllChanged();
+}