Add process.info MCP tool for PEB/TEB enumeration

Expose PEB address via provider interface and query it in the
ProcessMemory plugin using NtQueryInformationProcess. The new
process.info MCP tool returns the PEB VA and enumerates TEBs by
querying thread information via NtQuerySystemInformation and
NtQueryInformationThread for each thread in the target process.

src/mcp/mcp_bridge.h

@@ -60,6 +60,7 @@ private:
     QJsonObject toolUiAction(const QJsonObject& args);
     QJsonObject toolTreeSearch(const QJsonObject& args);
     QJsonObject toolNodeHistory(const QJsonObject& args);
+    QJsonObject toolProcessInfo(const QJsonObject& args);
 
     // Helpers
     QJsonObject makeTextResult(const QString& text, bool isError = false);