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/tests/check.hpp

@@ -0,0 +1,51 @@
+#pragma once
+
+// A tiny zero-dependency check framework so the test suite needs nothing but a
+// C++20 compiler. Each test executable returns 0 on success, 1 on any failure,
+// which is exactly what CTest interprets as pass/fail.
+
+#include <cstdio>
+
+namespace maj0test {
+inline int checks = 0;
+inline int failures = 0;
+}  // namespace maj0test
+
+// Variadic so that brace-init lists with commas, e.g. CHECK(Point{1, 2} == ...),
+// are passed through as a single condition instead of several macro arguments.
+#define CHECK(...)                                                           \
+    do {                                                                     \
+        ++::maj0test::checks;                                                \
+        if (!(__VA_ARGS__)) {                                                \
+            ++::maj0test::failures;                                          \
+            std::printf("  [FAIL] %s:%d  CHECK(%s)\n", __FILE__, __LINE__,   \
+                        #__VA_ARGS__);                                       \
+        }                                                                    \
+    } while (0)
+
+#define CHECK_THROWS(...)                                                    \
+    do {                                                                     \
+        ++::maj0test::checks;                                                \
+        bool threw = false;                                                  \
+        try {                                                                \
+            (void)(__VA_ARGS__);                                             \
+        } catch (...) {                                                      \
+            threw = true;                                                    \
+        }                                                                    \
+        if (!threw) {                                                        \
+            ++::maj0test::failures;                                          \
+            std::printf("  [FAIL] %s:%d  CHECK_THROWS(%s)\n", __FILE__,      \
+                        __LINE__, #__VA_ARGS__);                             \
+        }                                                                    \
+    } while (0)
+
+#define RUN(fn)                              \
+    do {                                     \
+        std::printf("[RUN ] %s\n", #fn);     \
+        fn();                                \
+    } while (0)
+
+#define REPORT()                                                             \
+    (std::printf("\n%d checks, %d failures\n", ::maj0test::checks,           \
+                 ::maj0test::failures),                                      \
+     ::maj0test::failures == 0 ? 0 : 1)