Vendor the maj0sted track layout library and link it into the editor

Drop-in copy of C:\Users\maj00r\Projects\maj0sted-master minus its web/
directory - the WASM frontend is not being ported, the editor drives the
same C++ API natively. What is left is plain C++20 with no dependencies:
domain model (niweleta, plan and profile geometry, fitting, parallelism),
project serialization, rail sampling and the editor document.

src/web/ribbon.cpp was missing from the library source list; added, since
without it the ribbon symbols never make it into the archive.

maj0sted/examples/basic_editor.cpp

@@ -0,0 +1,20 @@
+// Minimal walkthrough: create a map project and inspect its CRS.
+
+#include <cstdio>
+
+#include "maj0sted/maj0sted.hpp"
+
+using namespace maj0sted::domain;
+
+int main() {
+    std::printf("maj0sted %s\n\n", MAJ0STED_VERSION_STRING);
+
+    const MapProject project;  // defaults to EPSG:2180
+    std::printf("Map project CRS: EPSG:%d\n", project.crs().epsg());
+
+    const CartesianPosition position{500000.0, 300000.0};
+    std::printf("Sample position: x=%.1f m, y=%.1f m\n", position.x(),
+                position.y());
+
+    return 0;
+}