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_TPIStream.cpp

@@ -0,0 +1,86 @@
+#include "PDB_PCH.h"
+#include "PDB_TPIStream.h"
+#include "PDB_RawFile.h"
+#include "PDB_DirectMSFStream.h"
+#include "Foundation/PDB_Memory.h"
+
+namespace
+{
+	// the TPI stream always resides at index 2
+	static constexpr const uint32_t TPIStreamIndex = 2u;
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB::TPIStream::TPIStream(void) PDB_NO_EXCEPT
+	: m_stream()
+	, m_header()
+	, m_recordCount(0u)
+{
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB::TPIStream::TPIStream(TPIStream&& other) PDB_NO_EXCEPT
+	: m_stream(PDB_MOVE(other.m_stream))
+	, m_header(PDB_MOVE(other.m_header))
+	, m_recordCount(PDB_MOVE(other.m_recordCount))
+{
+	other.m_recordCount = 0u;
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB::TPIStream& PDB::TPIStream::operator=(TPIStream&& other) PDB_NO_EXCEPT
+{
+	if (this != &other)
+	{
+		m_stream = PDB_MOVE(other.m_stream);
+		m_header = PDB_MOVE(other.m_header);
+		m_recordCount = PDB_MOVE(other.m_recordCount);
+
+		other.m_recordCount = 0u;
+	}
+
+	return *this;
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB::TPIStream::TPIStream(const RawFile& file) PDB_NO_EXCEPT
+	: m_stream(file.CreateMSFStream<DirectMSFStream>(TPIStreamIndex)),
+	  m_header(m_stream.ReadAtOffset<TPI::StreamHeader>(0u)),
+	  m_recordCount(GetLastTypeIndex() - GetFirstTypeIndex())
+{
+}
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB_NO_DISCARD PDB::ErrorCode PDB::HasValidTPIStream(const RawFile& file) PDB_NO_EXCEPT
+{
+	DirectMSFStream stream = file.CreateMSFStream<DirectMSFStream>(TPIStreamIndex);
+	if (stream.GetSize() < sizeof(TPI::StreamHeader))
+	{
+		return ErrorCode::InvalidStream;
+	}
+
+	const TPI::StreamHeader header = stream.ReadAtOffset<TPI::StreamHeader>(0u);
+	if (header.version != TPI::StreamHeader::Version::V80)
+	{
+		return ErrorCode::UnknownVersion;
+	}
+
+	return ErrorCode::Success;
+}
+
+
+// ------------------------------------------------------------------------------------------------
+// ------------------------------------------------------------------------------------------------
+PDB_NO_DISCARD PDB::TPIStream PDB::CreateTPIStream(const RawFile& file) PDB_NO_EXCEPT
+{
+	return TPIStream { file };
+}