Fix IcedAssembler immediate overflow and unwrap invoke exceptions

- TryBind wraps Convert.ChangeType in TryChangeType so an immediate that
  overflows a candidate parameter type returns false (letting a wider overload
  be tried) instead of throwing OverflowException out of assembly. Verified:
  "mov eax, 4294967295" and "mov eax, -2147483649" no longer crash.
- Immediate now carries a boxed long OR ulong; TryParseImmediate parses decimal
  values above long.MaxValue via a ulong fallback, and hex via ulong. Previously
  such literals were rejected at parse time.
- Unwrap TargetInvocationException from method.Invoke so callers see the real
  Iced failure, not the reflection wrapper.

Tests: 231 passing, 4 skipped.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

WhiteMagicTest/Assembly/IcedAssemblerTests.cs

@@ -82,6 +82,32 @@ public class IcedAssemblerTests
         Assert.Equal(expected, jmp.NearBranchTarget);
     }
 
+    [Theory]
+    [InlineData("mov eax, 4294967295")]   // 0xFFFFFFFF — needs the uint overload, not int
+    [InlineData("mov eax, 0xFFFFFFFF")]    // same value, hex form
+    [InlineData("mov rax, 18446744073709551615")] // ulong.MaxValue — decimal above long.MaxValue
+    public void Assemble_binds_wide_unsigned_immediates(string source)
+    {
+        var assembler = new IcedAssembler(64);
+
+        byte[] code = assembler.Assemble(source);
+        Assert.NotEmpty(code);
+
+        Instruction[] instructions = Disassemble(code, 64, 0);
+        Assert.Single(instructions);
+        Assert.Equal(Mnemonic.Mov, instructions[0].Mnemonic);
+    }
+
+    [Fact]
+    public void Assemble_rejects_immediate_that_fits_no_overload_without_crashing()
+    {
+        var assembler = new IcedAssembler(64);
+
+        // -2147483649 is below int.MinValue and eax has no wider signed overload; must be a
+        // clean NotSupportedException, not an OverflowException escaping from ChangeType.
+        Assert.Throws<NotSupportedException>(() => assembler.Assemble("mov eax, -2147483649"));
+    }
+
     [Fact]
     public void Assemble_throws_on_unsupported_operand()
     {