Add Missing Includes Across src/slic3r/GUI (#16048)

* Add Missing Includes Across src/slic3r/GUI

Every GUI source and header now directly includes the headers declaring what it uses, rather than relying on the precompiled header or transitive includes. Generated with clang-tidy misc-include-cleaner, plus one hand edit making CalibrationPanel.hpp self-contained.

* Drop the OS-Specific Includes Added Outside Their Platform Guards

GLib, GTK, D-Bus and POSIX headers are only used inside platform #if blocks, which already include them. Added unconditionally at the top of the file they broke the Windows build.

* Add the clang-tidy Configuration That Generated These Includes

Only misc-include-cleaner's missing-include check, with the headers it must never suggest: per-platform, internal and OS-specific ones that would break other platforms or are not meant to be included directly.

* Match Windows Paths in the clang-tidy Ignore List

Header paths use backslashes on Windows, so every / in a pattern is now [/\\]. The Windows SDK headers are ignored alongside the other OS-specific ones, and the list is one pattern per line. Suggested by @raistlin7447 from a Windows clang-cl run.

src/slic3r/GUI/StepMeshDialog.cpp

@@ -1,7 +1,18 @@
 #include "StepMeshDialog.hpp"
 
+#include "libslic3r/Format/STEP.hpp"
+#include "slic3r/GUI/GUI_Utils.hpp"
+#include "slic3r/GUI/Widgets/StateColor.hpp"
+#include "slic3r/GUI/Widgets/Label.hpp"
+#include "slic3r/GUI/Widgets/HyperLink.hpp"
+#include "slic3r/GUI/MsgDialog.hpp"
+#include "libslic3r/LocalesUtils.hpp"
+#include "libslic3r/Thread.hpp"
 #include <thread>
+#include <wx/dialog.h>
+#include <wx/colour.h>
 #include <wx/event.h>
+#include <wx/gdicmn.h>
 #include <wx/sizer.h>
 #include <wx/slider.h>
 #include <wx/dcmemory.h>
@@ -13,6 +24,9 @@
 #include "Widgets/DialogButtons.hpp"
 #include "Widgets/RoundedRectangle.hpp"
 #include <chrono>
+#include <wx/string.h>
+#include <wx/textctrl.h>
+#include <wx/valtext.h>
 
 using namespace Slic3r;
 using namespace Slic3r::GUI;