chore: initial project import

backend/fleet/src/Fleet.Core/ErrorCode.cs

@@ -0,0 +1,28 @@
+namespace Fleet.Core;
+
+/// <summary>
+/// 错误码：snake_case 字符串。框架的错误码以 <c>fleet_</c> 开头，产品可以扩展自己的错误码。
+/// </summary>
+public readonly record struct ErrorCode(string Value)
+{
+    public override string ToString() => Value;
+}
+
+public static class FleetErrors
+{
+    public static readonly ErrorCode Unauthorized = new("fleet_unauthorized");
+    public static readonly ErrorCode Forbidden = new("fleet_forbidden");
+    public static readonly ErrorCode Unsupported = new("fleet_unsupported");
+    public static readonly ErrorCode InvalidParams = new("fleet_invalid_params");
+    public static readonly ErrorCode NotFound = new("fleet_not_found");
+    public static readonly ErrorCode Internal = new("fleet_internal");
+    public static readonly ErrorCode Timeout = new("fleet_timeout");
+    public static readonly ErrorCode NodeOffline = new("fleet_node_offline");
+    public static readonly ErrorCode NodePending = new("fleet_node_pending");
+    public static readonly ErrorCode NodeDisabled = new("fleet_node_disabled");
+    public static readonly ErrorCode NameConflict = new("fleet_name_conflict");
+    public static readonly ErrorCode JoinTokenInvalid = new("fleet_join_token_invalid");
+    public static readonly ErrorCode JoinTokenExpired = new("fleet_join_token_expired");
+    public static readonly ErrorCode ProofInvalid = new("fleet_proof_invalid");
+    public static readonly ErrorCode FrameTooLarge = new("fleet_frame_too_large");
+}