feat: Add unit tests and fakes for Crestron environment and data store

- Introduced `FakeCrestronEnvironment` and `FakeEthernetHelper` for testing purposes.
- Implemented `InMemoryCrestronDataStore` to facilitate unit tests for data storage.
- Created `DebugServiceTests` to validate the behavior of debug-related services.
- Added project files for unit tests targeting .NET 9.0 with necessary dependencies.
- Developed production adapters (`CrestronConsoleAdapter`, `CrestronDataStoreAdapter`, `CrestronEnvironmentAdapter`, `CrestronEthernetAdapter`) to interface with the Crestron SDK.
- Updated `Debug` class to utilize injected service abstractions instead of direct SDK calls.
- Enhanced `ControlSystem` initialization to register service adapters before usage.

src/PepperDash.Core/Adapters/CrestronEnvironmentAdapter.cs

@@ -0,0 +1,68 @@
+using System;
+using Crestron.SimplSharp;
+using PdCore = PepperDash.Core.Abstractions;
+
+namespace PepperDash.Core.Adapters;
+
+/// <summary>
+/// Production adapter — delegates ICrestronEnvironment calls to the real Crestron SDK.
+/// </summary>
+public sealed class CrestronEnvironmentAdapter : PdCore.ICrestronEnvironment
+{
+    // Subscribe once in constructor and re-raise as our event types.
+    private event EventHandler<PdCore.ProgramStatusEventArgs>? _programStatusChanged;
+    private event EventHandler<PdCore.PepperDashEthernetEventArgs>? _ethernetEventReceived;
+
+    public CrestronEnvironmentAdapter()
+    {
+        CrestronEnvironment.ProgramStatusEventHandler += type =>
+            _programStatusChanged?.Invoke(this, new PdCore.ProgramStatusEventArgs(MapProgramStatus(type)));
+
+        CrestronEnvironment.EthernetEventHandler += args =>
+            _ethernetEventReceived?.Invoke(this, new PdCore.PepperDashEthernetEventArgs(
+                args.EthernetEventType == eEthernetEventType.LinkDown
+                    ? PdCore.EthernetEventType.LinkDown
+                    : PdCore.EthernetEventType.LinkUp,
+                (short)args.EthernetAdapter));
+    }
+
+    public PdCore.DevicePlatform DevicePlatform =>
+        CrestronEnvironment.DevicePlatform == eDevicePlatform.Appliance
+            ? PdCore.DevicePlatform.Appliance
+            : PdCore.DevicePlatform.Server;
+
+    public PdCore.RuntimeEnvironment RuntimeEnvironment =>
+        CrestronEnvironment.RuntimeEnvironment == eRuntimeEnvironment.SimplSharpPro
+            ? PdCore.RuntimeEnvironment.SimplSharpPro
+            : PdCore.RuntimeEnvironment.Other;
+
+    public string NewLine => CrestronEnvironment.NewLine;
+
+    public uint ApplicationNumber => InitialParametersClass.ApplicationNumber;
+
+    public uint RoomId => uint.TryParse(InitialParametersClass.RoomId, out var r) ? r : 0;
+
+    public event EventHandler<PdCore.ProgramStatusEventArgs> ProgramStatusChanged
+    {
+        add => _programStatusChanged += value;
+        remove => _programStatusChanged -= value;
+    }
+
+    public event EventHandler<PdCore.PepperDashEthernetEventArgs> EthernetEventReceived
+    {
+        add => _ethernetEventReceived += value;
+        remove => _ethernetEventReceived -= value;
+    }
+
+    public string GetApplicationRootDirectory() =>
+        Crestron.SimplSharp.CrestronIO.Directory.GetApplicationRootDirectory();
+
+    private static PdCore.ProgramStatusEventType MapProgramStatus(eProgramStatusEventType type) =>
+        type switch
+        {
+            eProgramStatusEventType.Stopping => PdCore.ProgramStatusEventType.Stopping,
+            eProgramStatusEventType.Paused => PdCore.ProgramStatusEventType.Paused,
+            eProgramStatusEventType.Resumed => PdCore.ProgramStatusEventType.Resumed,
+            _ => PdCore.ProgramStatusEventType.Starting,
+        };
+}