GUI: Begin IPC mechanism to open files despite sandboxing

shared/shared.pro

@@ -13,6 +13,8 @@ TEMPLATE = lib
 CONFIG += staticlib
 CONFIG += c++17
 
+INCLUDEPATH += $$PWD/../sandbox/qssb.h/
+
 # The following define makes your compiler emit warnings if you use
 # any feature of Qt which has been marked as deprecated (the exact warnings
 # depend on your compiler). Please consult the documentation of the