Merge the track layout editor into cpp20-modules, ported to modules

The editor branch was written against headers and the PCH, both of which this
branch has done away with, so its own files were ported rather than merged: the
five headers it added are now interface units and their .cpp files module
implementation units.

- editor/{puwg1992,polandmap,turnouts,orthophoto} become eu07.editor.* modules,
  application/planpanel becomes eu07.application.planpanel. The plan tool keeps
  to its own module rather than joining the eu07.simcore partitions: it stands on
  the editor's libraries and eu07.application.uilayer, not on the simulation core,
  so :editoruilayer can export import it without a cycle.
- glm arrives by import eu07.glm, never by include, as the rest of the tree does.
  maj0sted is header-only and glm-free, so its headers stay includes in the global
  module fragment - every unit that names those types includes them itself, since
  a global fragment is not visible across units.
- the one textual conflict was :editoruilayer's include block against this
  branch's imports; resolved this branch's way plus the planpanel import.

Builds with clang 22 (-DWITH_BETTER_RENDERER=OFF) and starts into the editor on
empty ground with -editor alone.

application/editormode.cppm

@@ -60,10 +60,7 @@ class editor_mode : public application_mode
 	void on_key(int Key, int Scancode, int Action, int Mods) override;
 	void on_cursor_pos(double Horizontal, double Vertical) override;
 	void on_mouse_button(int Button, int Action, int Mods) override;
-	void on_scroll(double const Xoffset, double const Yoffset) override
-	{
-		;
-	}
+	void on_scroll(double const Xoffset, double const Yoffset) override;
 	void on_window_resize(int w, int h) override
 	{
 		;
@@ -129,6 +126,10 @@ class editor_mode : public application_mode
 	editormode_input m_input;
 	static TCamera Camera;
 
+	// camera orientation from before the plan view took over, to be handed back when it is left
+	bool m_orthoactive{false};
+	glm::vec3 m_orthoangle{0.0f};
+
 	// focus (smooth camera fly-to) state
 	static bool m_focus_active;
 	glm::dvec3 m_focus_start_pos{0.0,0.0,0.0};