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/Agents/HostStatusService.cs

@@ -0,0 +1,67 @@
+using Fleet.Core;
+using MoShiro.Protocol;
+
+namespace MoShiro.Backend.Application;
+
+/// <summary>
+/// <c>moshiro.host</c>：Agent 每隔几秒上报的主机资源占用快照。最新值放在内存里并实时推给订阅者；每个 Agent 每分钟存一个样本做历史。
+/// 快照里没有 CPU 型号、主机名、网卡名和 IP（Agent 根本不采集它们）。
+/// </summary>
+public sealed class HostStatusService
+{
+    private static readonly TimeSpan s_stale = TimeSpan.FromSeconds(15);
+
+    private readonly AgentRuntime _runtime;
+    private readonly IHostStore _store;
+    private readonly LiveHub _live;
+    private readonly TimeProvider _time;
+    private readonly Dictionary<NodeId, long> _lastSavedMinute = [];
+    private readonly object _gate = new();
+
+    public HostStatusService(AgentRuntime runtime, IHostStore store, LiveHub live, TimeProvider time)
+    {
+        _runtime = runtime;
+        _store = store;
+        _live = live;
+        _time = time;
+    }
+
+    public async ValueTask OnHostAsync(NodeId agent, HostSnapshot snapshot, CancellationToken ct)
+    {
+        long now = _time.GetUtcNow().ToUnixTimeMilliseconds();
+        snapshot.AtUtcMs = now; // 以 Backend 收到的时间为准：节点的时钟不可信
+        AgentRuntimeState state = _runtime.Get(agent);
+        state.Host = snapshot;
+        state.HostReceivedAtMs = now;
+        _live.Publish(new HostSignal(agent, snapshot));
+
+        long minute = now - (now % 60_000);
+        bool save;
+        lock (_gate)
+        {
+            save = !_lastSavedMinute.TryGetValue(agent, out long last) || last != minute;
+            if (save)
+            {
+                _lastSavedMinute[agent] = minute;
+            }
+        }
+
+        if (save)
+        {
+            await _store.SaveAsync(agent, minute, snapshot, ct);
+        }
+    }
+
+    /// <summary>最新快照；超过 15 秒没有更新就是过期（Agent 离线或者没有开启上报）。</summary>
+    public (HostSnapshot? Host, bool Stale) Latest(NodeId agent)
+    {
+        if (!_runtime.TryGet(agent, out AgentRuntimeState? state) || state.Host is null)
+        {
+            return (null, true);
+        }
+
+        return (state.Host, _time.GetUtcNow().ToUnixTimeMilliseconds() - state.HostReceivedAtMs > s_stale.TotalMilliseconds);
+    }
+
+    public ValueTask<IReadOnlyList<HostSample>> HistoryAsync(NodeId agent, long fromMs, long toMs, CancellationToken ct) => _store.ReadAsync(agent, fromMs, toMs, ct);
+}