Implement core diagnostic memory layer, execution helpers, and high-level facade slices

Implemented:
- Core: UTF-16 ReadString boundary/alignment fix, target bitness and process id on MemoryBase
- function interception: PatchManager, DetourManager, InstructionAnalyzer, MainThreadDispatcher
- Execution: BackgroundTaskExecutor, InProcessInvoker
- High-level: Magic facade, RemotePointer, async wrappers
- Discovery/external code loading/Window groundwork (PEB/TEB, pattern scanning, raw allocations, DLL external code loading, window/input)

Tests: 180 passing, 4 integration/interactive tests skipped.

WhiteMagicTest/Input/InputSimulatorTests.cs

@@ -0,0 +1,41 @@
+using System.Diagnostics;
+using WhiteMagic.Input;
+using WhiteMagic.Windows;
+using Xunit;
+
+namespace WhiteMagicTest.Input;
+
+public sealed class InputSimulatorTests
+{
+    [Fact(Skip = "Interactive input test - requires a visible window")]
+    public void SendKeys_to_current_window_does_not_throw()
+    {
+        using var process = Process.GetCurrentProcess();
+        IntPtr handle = process.MainWindowHandle != IntPtr.Zero
+            ? process.MainWindowHandle
+            : WindowFactory.GetWindows().FirstOrDefault()?.Handle ?? IntPtr.Zero;
+
+        if (handle == IntPtr.Zero)
+            return;
+
+        var simulator = new InputSimulator();
+        bool result = simulator.SendKeys(handle, "ab");
+        Assert.True(result);
+    }
+
+    [Fact(Skip = "Interactive input test - requires a visible window")]
+    public void SendMouseClick_to_current_window_does_not_throw()
+    {
+        using var process = Process.GetCurrentProcess();
+        IntPtr handle = process.MainWindowHandle != IntPtr.Zero
+            ? process.MainWindowHandle
+            : WindowFactory.GetWindows().FirstOrDefault()?.Handle ?? IntPtr.Zero;
+
+        if (handle == IntPtr.Zero)
+            return;
+
+        var simulator = new InputSimulator();
+        bool result = simulator.SendMouseClick(handle, 10, 20, MouseButton.Left);
+        Assert.True(result);
+    }
+}