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/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;
+}