Add in-game developer console (MrGameEng.DevConsole)

Core gains a static Log (Debug/Info/Warning/Error + event); the engine
logs key events like scene switches. The console captures Log output
into a 2048-line ring buffer and executes registered commands with
input history (up/down), Tab prefix completion and scrolling
(PageUp/PageDown/End/wheel). Built-ins: help, clear, echo, timescale,
close, quit; games register their own (sample: stress/main/beep).

Console core is pure logic covered by headless tests; the Myra overlay
renders a single label rebuilt only when the Revision counter moves -
an idle or closed console costs nothing per frame. Toggled with the
backquote key; sample gameplay hotkeys are suppressed while open.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

samples/MrGameEng.Sample/MrGameEng.Sample.csproj

@@ -12,6 +12,7 @@
     <ProjectReference Include="..\..\src\MrGameEng.Audio\MrGameEng.Audio.csproj" />
     <ProjectReference Include="..\..\src\MrGameEng.Assets\MrGameEng.Assets.csproj" />
     <ProjectReference Include="..\..\src\MrGameEng.UI\MrGameEng.UI.csproj" />
+    <ProjectReference Include="..\..\src\MrGameEng.DevConsole\MrGameEng.DevConsole.csproj" />
     <ProjectReference Include="..\..\src\MrGameEng.Assets.Generator\MrGameEng.Assets.Generator.csproj"
                       OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
   </ItemGroup>

samples/MrGameEng.Sample/SampleSystems.cs

@@ -12,10 +12,16 @@ namespace MrGameEng.Sample;
 
 /// <summary>Управление игроком (WASD/стрелки) и прыжок-писк на пробел.</summary>
 public sealed class PlayerControlSystem(
-    Entity player, ActionMap<SampleAction> actions, AudioManager audio, SoundEffect beep) : BaseSystem
+    Entity player, ActionMap<SampleAction> actions, AudioManager audio, SoundEffect beep,
+    MrGameEng.DevConsole.DevConsole console) : BaseSystem
 {
     protected override void OnUpdateGroup()
     {
+        if (console.IsOpen)
+        {
+            return;
+        }
+
         ref var transform = ref player.GetComponent<Transform2D>();
         var move = new Vector2(
             actions.GetAxis(SampleAction.MoveLeft, SampleAction.MoveRight),
@@ -131,6 +137,11 @@ public sealed class SceneHotkeysSystem(
 {
     protected override void OnUpdateGroup()
     {
+        if (context.Services.Get<MrGameEng.DevConsole.DevConsole>().IsOpen)
+        {
+            return;
+        }
+
         if (actions.IsPressed(SampleAction.Pause))
         {
             context.Clock.TimeScale = context.Clock.TimeScale > 0f ? 0f : 1f;

samples/MrGameEng.Sample/Scenes/MainScene.cs

@@ -3,6 +3,7 @@ using Microsoft.Xna.Framework;
 using MrGameEng.Assets;
 using MrGameEng.Audio;
 using MrGameEng.Core;
+using MrGameEng.DevConsole;
 using MrGameEng.Graphics;
 using MrGameEng.Input;
 using MrGameEng.UI;
@@ -113,7 +114,25 @@ public sealed class MainScene : Scene
         panel.Widgets.Add(switchButton);
         desktop.Root = panel;
 
-        UpdateSystems.Add(new PlayerControlSystem(player, actions, audio, beep));
+        // Консоль разработчика (клавиша `) — последней, чтобы рисовалась поверх UI.
+        var console = this.UseDevConsole();
+        console.Register("stress", "switch to the stress scene", (_, _) =>
+        {
+            if (!Context.Scenes.IsTransitioning)
+            {
+                Context.Scenes.Switch(new StressScene(), Transition.Fade(0.8f));
+            }
+        });
+        console.Register("main", "switch to the main scene", (_, _) =>
+        {
+            if (!Context.Scenes.IsTransitioning)
+            {
+                Context.Scenes.Switch(new MainScene(), Transition.Fade(0.8f));
+            }
+        });
+        console.Register("beep", "play the beep sound", (_, _) => audio.Play(beep));
+
+        UpdateSystems.Add(new PlayerControlSystem(player, actions, audio, beep, console));
         UpdateSystems.Add(new BounceSystem(WorldBounds));
         UpdateSystems.Add(new CameraControlSystem(camera, player, input));
         UpdateSystems.Add(new SceneHotkeysSystem(Context, actions, () => new StressScene(), Transition.Fade(0.8f)));

samples/MrGameEng.Sample/Scenes/StressScene.cs

@@ -2,6 +2,7 @@ using Friflo.Engine.ECS;
 using Microsoft.Xna.Framework;
 using MrGameEng.Assets;
 using MrGameEng.Core;
+using MrGameEng.DevConsole;
 using MrGameEng.Graphics;
 using MrGameEng.Input;
 using MrGameEng.UI;
@@ -71,6 +72,8 @@ public sealed class StressScene : Scene
         panel.Widgets.Add(backButton);
         desktop.Root = panel;
 
+        this.UseDevConsole(); // поверх UI
+
         UpdateSystems.Add(new BounceSystem(WorldBounds));
         UpdateSystems.Add(new StressCameraSystem(camera, input));
         UpdateSystems.Add(new SceneHotkeysSystem(Context, actions, () => new MainScene(), Transition.Wipe(0.8f, Color.DarkSlateBlue)));