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/Auth/LoginRateLimiter.cs

@@ -0,0 +1,57 @@
+using System.Collections.Concurrent;
+
+namespace MoShiro.Backend.Application;
+
+/// <summary>登录限流：每个来源在滑动的一分钟内最多尝试若干次。</summary>
+public sealed class LoginRateLimiter
+{
+    private readonly ConcurrentDictionary<string, Queue<long>> _attempts = new();
+    private readonly BackendOptions _options;
+    private readonly TimeProvider _time;
+
+    public LoginRateLimiter(BackendOptions options, TimeProvider time)
+    {
+        _options = options;
+        _time = time;
+    }
+
+    /// <summary>登记一次尝试；超限时返回 false 与建议的重试等待秒数。</summary>
+    public bool TryAcquire(string source, out int retryAfterSeconds)
+    {
+        long now = _time.GetUtcNow().ToUnixTimeMilliseconds();
+        Queue<long> queue = _attempts.GetOrAdd(source, _ => new Queue<long>());
+        lock (queue)
+        {
+            while (queue.Count > 0 && now - queue.Peek() >= 60_000)
+            {
+                queue.Dequeue();
+            }
+
+            if (queue.Count >= _options.LoginAttemptsPerMinute)
+            {
+                retryAfterSeconds = (int)Math.Max(1, (60_000 - (now - queue.Peek()) + 999) / 1000);
+                return false;
+            }
+
+            queue.Enqueue(now);
+            retryAfterSeconds = 0;
+            return true;
+        }
+    }
+
+    /// <summary>清理很久没有尝试的来源，避免字典无限增长。</summary>
+    public void Prune()
+    {
+        long now = _time.GetUtcNow().ToUnixTimeMilliseconds();
+        foreach ((string key, Queue<long> queue) in _attempts)
+        {
+            lock (queue)
+            {
+                if (queue.Count == 0 || now - queue.Peek() >= 60_000)
+                {
+                    _attempts.TryRemove(key, out _);
+                }
+            }
+        }
+    }
+}