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/ProcessEnvironment/ManagedPebTests.cs

@@ -0,0 +1,28 @@
+using System.Diagnostics;
+using WhiteMagic;
+using WhiteMagic.ProcessEnvironment;
+using Xunit;
+
+namespace WhiteMagicTest.ProcessEnvironment;
+
+public sealed class ManagedPebTests
+{
+    [Fact]
+    public void Read_current_process_peb_fields_returns_plausible_values()
+    {
+        using var magic = Magic.OpenInProcess();
+        var peb = new ManagedPeb(magic.Memory);
+
+        Assert.NotEqual(IntPtr.Zero, peb.ReadPebAddress());
+        Assert.NotEqual(IntPtr.Zero, peb.ReadImageBaseAddress());
+
+        byte beingDebugged = peb.ReadBeingDebugged();
+        Assert.True(beingDebugged == 0 || beingDebugged == 1);
+
+        Assert.NotEqual(IntPtr.Zero, peb.ReadLdrAddress());
+
+        // The in-process test process is native to the host architecture, so
+        // it is not running under WOW64.
+        Assert.False(peb.ReadIsWow64Process());
+    }
+}