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.

WhiteMagic/Windows/WindowFactory.cs

@@ -0,0 +1,74 @@
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Runtime.CompilerServices;
+using WhiteMagic.Native;
+
+namespace WhiteMagic.Windows;
+
+/// <summary>
+/// Factory for enumerating and locating <see cref="RemoteWindow"/> instances.
+/// </summary>
+public static class WindowFactory
+{
+    /// <summary>Enumerates all top-level windows.</summary>
+    public static unsafe IEnumerable<RemoteWindow> GetWindows()
+    {
+        var handles = new List<IntPtr>();
+        GCHandle gch = GCHandle.Alloc(handles);
+        try
+        {
+            delegate* unmanaged[Stdcall]<IntPtr, IntPtr, int> callback = &EnumWindowsCallback;
+            NativeMethods.EnumWindows((nint)callback, GCHandle.ToIntPtr(gch));
+        }
+        finally
+        {
+            gch.Free();
+        }
+
+        return handles.Select(static h => new RemoteWindow(h));
+    }
+
+    /// <summary>Returns all top-level windows with the specified class name.</summary>
+    public static IEnumerable<RemoteWindow> GetWindowsByClassName(string className)
+    {
+        if (className is null)
+            throw new ArgumentNullException(nameof(className));
+
+        return GetWindows().Where(w => w.ClassName.Equals(className, StringComparison.Ordinal));
+    }
+
+    /// <summary>Returns all top-level windows owned by the specified process.</summary>
+    public static IEnumerable<RemoteWindow> GetWindowsByProcessId(int processId)
+    {
+        return GetWindows().Where(w => w.ProcessId == (uint)processId);
+    }
+
+    /// <summary>Returns the first top-level window with the specified class name.</summary>
+    public static RemoteWindow? GetWindowByClassName(string className)
+    {
+        return GetWindowsByClassName(className).FirstOrDefault();
+    }
+
+    /// <summary>
+    /// Returns the main window of a process. When <see cref="Process.MainWindowHandle"/>
+    /// is unavailable, falls back to the first enumerated window owned by the process.
+    /// </summary>
+    public static RemoteWindow? GetMainWindow(System.Diagnostics.Process process)
+    {
+        if (process is null)
+            throw new ArgumentNullException(nameof(process));
+
+        if (process.MainWindowHandle != IntPtr.Zero)
+            return new RemoteWindow(process.MainWindowHandle);
+
+        return GetWindowsByProcessId(process.Id).FirstOrDefault();
+    }
+
+    [UnmanagedCallersOnly(CallConvs = new[] { typeof(CallConvStdcall) })]
+    private static int EnumWindowsCallback(IntPtr hWnd, IntPtr lParam)
+    {
+        var handles = (List<IntPtr>)GCHandle.FromIntPtr(lParam).Target!;
+        handles.Add(hWnd);
+        return 1; // Continue enumeration.
+    }
+}