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

@@ -2,7 +2,7 @@ namespace Fleet.Server;
 
 public sealed class FleetServerOptions
 {
-    /// <summary>节点 ID 的类型前缀，Monitor 使用 <c>agt</c>。</summary>
+    /// <summary>节点 ID 的类型前缀，MoShiro 使用 <c>agt</c>。</summary>
     public string NodeIdPrefix { get; set; } = "node";
 
     public int MaxFrameBytes { get; set; } = 16 << 20;