fix: add missing symbol store and PDB debug info sources

These files were referenced in CMakeLists.txt and main.cpp but
never committed, breaking the CI build.

src/imports/pe_debug_info.h

@@ -0,0 +1,20 @@
+#pragma once
+#include <QString>
+#include <cstdint>
+
+namespace rcx {
+
+class Provider;
+
+struct PdbDebugInfo {
+    QString pdbName;      // e.g. "ntoskrnl.pdb"
+    QString guidString;   // 32 hex chars, no dashes, uppercase
+    uint32_t age = 0;
+    bool valid = false;
+};
+
+// Extract PDB debug info (GUID, age, filename) from a PE module in memory.
+// Reads DOS header → PE header → debug directory → CodeView RSDS record.
+PdbDebugInfo extractPdbDebugInfo(const Provider& prov, uint64_t moduleBase);
+
+} // namespace rcx