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/PDB_RawFile.h

@@ -0,0 +1,66 @@
+// 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 "Foundation/PDB_Macros.h"
+#include "PDB_CoalescedMSFStream.h"
+
+
+// https://llvm.org/docs/PDB/index.html
+namespace PDB
+{
+	struct SuperBlock;
+
+
+	class PDB_NO_DISCARD RawFile
+	{
+	public:
+		RawFile(RawFile&& other) PDB_NO_EXCEPT;
+		RawFile& operator=(RawFile&& other) PDB_NO_EXCEPT;
+
+		explicit RawFile(const void* data) PDB_NO_EXCEPT;
+		~RawFile(void) PDB_NO_EXCEPT;
+
+		// Creates any type of MSF stream.
+		template <typename T>
+		PDB_NO_DISCARD T CreateMSFStream(uint32_t streamIndex) const PDB_NO_EXCEPT;
+
+		// Creates any type of MSF stream with the given size.
+		template <typename T>
+		PDB_NO_DISCARD T CreateMSFStream(uint32_t streamIndex, uint32_t streamSize) const PDB_NO_EXCEPT;
+
+
+		// Returns the SuperBlock.
+		PDB_NO_DISCARD inline const SuperBlock* GetSuperBlock(void) const PDB_NO_EXCEPT
+		{
+			return m_superBlock;
+		}
+
+		// Returns the number of streams in the PDB file.
+		PDB_NO_DISCARD inline uint32_t GetStreamCount(void) const PDB_NO_EXCEPT
+		{
+			return m_streamCount;
+		}
+
+		// Returns the size of the stream with the given index, taking into account nil page sizes.
+		PDB_NO_DISCARD inline uint32_t GetStreamSize(uint32_t streamIndex) const PDB_NO_EXCEPT
+		{
+			const uint32_t streamSize = m_streamSizes[streamIndex];
+
+			return (streamSize == NilPageSize) ? 0u : streamSize;
+		}
+
+	private:
+		const void* m_data;
+		const SuperBlock* m_superBlock;
+		CoalescedMSFStream m_directoryStream;
+
+		// stream directory
+		uint32_t m_streamCount;
+		const uint32_t* m_streamSizes;
+		const uint32_t** m_streamBlocks;
+
+		PDB_DISABLE_COPY(RawFile);
+	};
+}