refactor!: rename the project from Monitor to MoShiro [CI]

Namespaces, assemblies, solution, binaries, images, systemd units, config paths, environment variables, protocol methods and the Linux user are all renamed. Breaking: existing databases, node identities and installed units must be recreated.

backend/src/MoShiro.Backend.Application/Live/LiveHub.cs

@@ -0,0 +1,66 @@
+using System.Collections.Concurrent;
+using System.Threading.Channels;
+using Fleet.Core;
+using MoShiro.Protocol;
+
+namespace MoShiro.Backend.Application;
+
+/// <summary>发布到 SSE 订阅者的信号。SSE 只负责“更快地获得变化”，推送的内容都能由 REST 查询重建。</summary>
+public abstract record LiveSignal;
+
+/// <summary>节点上下线等。</summary>
+public sealed record NodeSignal(string Kind, string Id, bool Online, long AtMs) : LiveSignal;
+
+/// <summary>某条序列有新的原始块入库。</summary>
+public sealed record ChunkSignal(NodeId AgentId, string Series) : LiveSignal;
+
+public sealed record TestSignal(TestId TestId) : LiveSignal;
+
+/// <summary>某个 Agent 的主机资源占用有了新的快照（实时推给展示页）。</summary>
+public sealed record HostSignal(NodeId AgentId, HostSnapshot Host) : LiveSignal;
+
+public sealed class LiveSubscription : IDisposable
+{
+    private readonly LiveHub _hub;
+    private readonly Channel<LiveSignal> _channel = Channel.CreateBounded<LiveSignal>(new BoundedChannelOptions(256) { FullMode = BoundedChannelFullMode.DropOldest });
+
+    internal LiveSubscription(LiveHub hub)
+    {
+        _hub = hub;
+    }
+
+    public ChannelReader<LiveSignal> Reader => _channel.Reader;
+
+    internal void Post(LiveSignal signal) => _channel.Writer.TryWrite(signal);
+
+    public void Dispose()
+    {
+        _hub.Remove(this);
+        _channel.Writer.TryComplete();
+    }
+}
+
+/// <summary>内存中的发布订阅：入库、节点上下线、测试状态变化都经过这里。</summary>
+public sealed class LiveHub
+{
+    private readonly ConcurrentDictionary<LiveSubscription, byte> _subscriptions = new();
+
+    public int SubscriberCount => _subscriptions.Count;
+
+    public LiveSubscription Subscribe()
+    {
+        var subscription = new LiveSubscription(this);
+        _subscriptions[subscription] = 0;
+        return subscription;
+    }
+
+    public void Publish(LiveSignal signal)
+    {
+        foreach (LiveSubscription subscription in _subscriptions.Keys)
+        {
+            subscription.Post(signal);
+        }
+    }
+
+    internal void Remove(LiveSubscription subscription) => _subscriptions.TryRemove(subscription, out _);
+}