Add process discovery helpers and Magic facade accessors

Introduces ApplicationFinder (by name/title/handle), Magic.Open overloads, and Magic.Threads/Regions/QueryRegion accessors. Closes section 3 of add-thread-region-finder and updates tasks/comparison doc.

WhiteMagicTest/MagicFacadeTests.cs

@@ -0,0 +1,44 @@
+using System.Linq;
+using WhiteMagic;
+using WhiteMagic.Memory;
+using WhiteMagic.Native;
+using WhiteMagic.Thread;
+using Xunit;
+
+namespace WhiteMagicTest;
+
+/// <summary>
+/// Tests for the convenience accessors exposed directly on <see cref="Magic"/>.
+/// </summary>
+public sealed class MagicFacadeTests
+{
+    [Fact]
+    public void QueryRegion_returns_region_containing_image_base()
+    {
+        using var magic = Magic.OpenInProcess();
+        MemoryRegion region = magic.QueryRegion(magic.Memory.ImageBase);
+        Assert.True(region.Contains(magic.Memory.ImageBase));
+    }
+
+    [Fact]
+    public void Regions_enumerates_region_containing_image_base()
+    {
+        using var magic = Magic.OpenInProcess();
+
+        bool found = magic.Regions.Any(r => r.Contains(magic.Memory.ImageBase));
+
+        Assert.True(found);
+    }
+
+    [Fact]
+    public void Threads_factory_enumerates_current_thread()
+    {
+        using var magic = Magic.OpenInProcess();
+        ThreadFactory factory = magic.Threads;
+
+        int currentOsId = (int)NativeMethods.GetCurrentThreadId();
+        bool found = factory.Enumerate().Any(t => t.Id == currentOsId);
+
+        Assert.True(found);
+    }
+}