feat: PDB import via RawPDB, no msdia140.dll dependency

Replace DIA SDK COM-based PDB importer with RawPDB (MolecularMatters)
which reads PDB files directly via memory-mapped I/O. Adds File menu
"Import PDB..." dialog with type filtering, selection, and progress.

- Vendor raw_pdb into third_party/
- Two-phase API: enumeratePdbTypes() + importPdbSelected()
- Full recursive import of structs/unions/arrays/pointers/bitfields
- PDB import dialog with name filter, select-all, type count
- Benchmark: 1654 types from ntkrnlmp.pdb in 16ms
- Reorganize import/export files into src/imports/

third_party/raw_pdb/src/Foundation/PDB_ArrayView.h

@@ -0,0 +1,68 @@
+// Copyright 2011-2022, Molecular Matters GmbH <office@molecular-matters.com>
+// See LICENSE.txt for licensing details (2-clause BSD License: https://opensource.org/licenses/BSD-2-Clause)
+
+#pragma once
+
+#include "PDB_Macros.h"
+#include "PDB_Assert.h"
+
+
+namespace PDB
+{
+	// A read-only view into arrays of any type and length.
+	template <typename T>
+	class PDB_NO_DISCARD ArrayView
+	{
+	public:
+		// Constructs an array view from a C array with explicit length.
+		inline constexpr explicit ArrayView(const T* const array, size_t length) PDB_NO_EXCEPT
+			: m_data(array)
+			, m_length(length)
+		{
+		}
+
+		PDB_DEFAULT_COPY_CONSTRUCTOR(ArrayView);
+		PDB_DEFAULT_MOVE_CONSTRUCTOR(ArrayView);
+
+		// Provides read-only access to the underlying array.
+		PDB_NO_DISCARD inline constexpr const T* Decay(void) const PDB_NO_EXCEPT
+		{
+			return m_data;
+		}
+
+		// Returns the length of the view.
+		PDB_NO_DISCARD inline constexpr size_t GetLength(void) const PDB_NO_EXCEPT
+		{
+			return m_length;
+		}
+
+		// Returns the i-th element.
+		PDB_NO_DISCARD inline const T& operator[](size_t i) const PDB_NO_EXCEPT
+		{
+			PDB_ASSERT(i < GetLength(), "Index %zu out of bounds [0, %zu).", i, GetLength());
+			return m_data[i];
+		}
+
+
+		// ------------------------------------------------------------------------------------------------
+		// Range-based for-loop support
+		// ------------------------------------------------------------------------------------------------
+
+		PDB_NO_DISCARD inline const T* begin(void) const PDB_NO_EXCEPT
+		{
+			return m_data;
+		}
+
+		PDB_NO_DISCARD inline const T* end(void) const PDB_NO_EXCEPT
+		{
+			return m_data + m_length;
+		}
+
+	private:
+		const T* const m_data;
+		const size_t m_length;
+
+		PDB_DISABLE_MOVE_ASSIGNMENT(ArrayView);
+		PDB_DISABLE_COPY_ASSIGNMENT(ArrayView);
+	};
+}