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.Tests/Fakes/CrestronConsoleFakes.cs

@@ -0,0 +1,38 @@
+using PepperDash.Core.Abstractions;
+
+namespace PepperDash.Core.Tests.Fakes;
+
+/// <summary>
+/// No-op ICrestronConsole that captures output for test assertions.
+/// </summary>
+public class CapturingCrestronConsole : ICrestronConsole
+{
+    public List<string> Lines { get; } = new();
+    public List<string> CommandResponses { get; } = new();
+    public List<(string Command, string HelpText)> RegisteredCommands { get; } = new();
+
+    public void PrintLine(string message) => Lines.Add(message);
+    public void Print(string message) => Lines.Add(message);
+    public void ConsoleCommandResponse(string message) => CommandResponses.Add(message);
+
+    public void AddNewConsoleCommand(
+        Action<string> callback,
+        string command,
+        string helpText,
+        ConsoleAccessLevel accessLevel)
+    {
+        RegisteredCommands.Add((command, helpText));
+    }
+}
+
+/// <summary>
+/// Minimal no-op ICrestronConsole that discards all output. Useful when you only
+/// care about the system under test and not what it logs.
+/// </summary>
+public class NoOpCrestronConsole : ICrestronConsole
+{
+    public void PrintLine(string message) { }
+    public void Print(string message) { }
+    public void ConsoleCommandResponse(string message) { }
+    public void AddNewConsoleCommand(Action<string> _, string __, string ___, ConsoleAccessLevel ____) { }
+}

src/PepperDash.Core.Tests/Fakes/CrestronEnvironmentFakes.cs

@@ -0,0 +1,46 @@
+using PepperDash.Core.Abstractions;
+
+namespace PepperDash.Core.Tests.Fakes;
+
+/// <summary>
+/// Configurable ICrestronEnvironment for unit tests.
+/// Defaults: Appliance / SimplSharpPro / ApplicationNumber=1.
+/// </summary>
+public class FakeCrestronEnvironment : ICrestronEnvironment
+{
+    public DevicePlatform DevicePlatform { get; set; } = DevicePlatform.Appliance;
+    public RuntimeEnvironment RuntimeEnvironment { get; set; } = RuntimeEnvironment.SimplSharpPro;
+    public string NewLine { get; set; } = "\r\n";
+    public uint ApplicationNumber { get; set; } = 1;
+    public uint RoomId { get; set; } = 0;
+
+    public event EventHandler<ProgramStatusEventArgs>? ProgramStatusChanged;
+    public event EventHandler<PepperDashEthernetEventArgs>? EthernetEventReceived;
+
+    public string GetApplicationRootDirectory() => System.IO.Path.GetTempPath();
+
+    /// <summary>Simulates a program status event for tests.</summary>
+    public void RaiseProgramStatus(ProgramStatusEventType type) =>
+        ProgramStatusChanged?.Invoke(this, new ProgramStatusEventArgs(type));
+
+    /// <summary>Simulates an ethernet event for tests.</summary>
+    public void RaiseEthernetEvent(EthernetEventType type, short adapter = 0) =>
+        EthernetEventReceived?.Invoke(this, new PepperDashEthernetEventArgs(type, adapter));
+}
+
+/// <summary>
+/// No-op IEthernetHelper that returns configurable values.
+/// </summary>
+public class FakeEthernetHelper : IEthernetHelper
+{
+    private readonly Dictionary<EthernetParameterType, string> _values = new();
+
+    public FakeEthernetHelper Seed(EthernetParameterType param, string value)
+    {
+        _values[param] = value;
+        return this;
+    }
+
+    public string GetEthernetParameter(EthernetParameterType parameter, short ethernetAdapterId) =>
+        _values.TryGetValue(parameter, out var v) ? v : string.Empty;
+}

src/PepperDash.Core.Tests/Fakes/InMemoryCrestronDataStore.cs

@@ -0,0 +1,59 @@
+using PepperDash.Core.Abstractions;
+
+namespace PepperDash.Core.Tests.Fakes;
+
+/// <summary>
+/// In-memory ICrestronDataStore backed by a dictionary.
+/// Use in unit tests to verify that keys are read from and written to the store correctly.
+/// </summary>
+public class InMemoryCrestronDataStore : ICrestronDataStore
+{
+    private readonly Dictionary<string, object> _store = new();
+
+    public bool Initialized { get; private set; }
+
+    public void InitStore() => Initialized = true;
+
+    public bool TryGetLocalInt(string key, out int value)
+    {
+        if (_store.TryGetValue(key, out var raw) && raw is int i)
+        {
+            value = i;
+            return true;
+        }
+        value = 0;
+        return false;
+    }
+
+    public bool SetLocalInt(string key, int value)
+    {
+        _store[key] = value;
+        return true;
+    }
+
+    public bool SetLocalUint(string key, uint value)
+    {
+        _store[key] = (int)value;
+        return true;
+    }
+
+    public bool TryGetLocalBool(string key, out bool value)
+    {
+        if (_store.TryGetValue(key, out var raw) && raw is bool b)
+        {
+            value = b;
+            return true;
+        }
+        value = false;
+        return false;
+    }
+
+    public bool SetLocalBool(string key, bool value)
+    {
+        _store[key] = value;
+        return true;
+    }
+
+    /// <summary>Seeds a key for testing read paths.</summary>
+    public void Seed(string key, object value) => _store[key] = value;
+}