do sessions in memory and also fix glaring security hole

Femto.Modules.Auth/Infrastructure/SessionStorage.cs

@@ -0,0 +1,30 @@
+using Femto.Modules.Auth.Models;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace Femto.Modules.Auth.Infrastructure;
+
+internal class SessionStorage(MemoryCacheOptions? options = null)
+{
+    private readonly IMemoryCache _storage = new MemoryCache(options ?? new MemoryCacheOptions());
+
+    public Task<Session?> GetSession(string id)
+    {
+        return Task.FromResult(this._storage.Get<Session>(id));
+    }
+
+    public Task AddSession(Session session)
+    {
+        using var entry = this._storage.CreateEntry(session.Id);
+        entry.Value = session;
+        entry.SetAbsoluteExpiration(session.Expires);
+
+        return Task.CompletedTask;
+    }
+
+    public Task DeleteSession(string id)
+    {
+        this._storage.Remove(id);
+
+        return Task.CompletedTask;
+    }
+}