Improve binary scenery format (v5): streaming reader, smaller files, headless parallel bake

- Reader is buffer-based and streaming: the twin is read once and parsed by
  pointer, entries decoded on demand (no per-byte stream, no vector-of-entry
  materialisation), string tokens served as views into the buffer.
- Format v5 is markedly smaller without compression: string interning with
  varint indices, entry type packed into the head varint, integers as zig-zag
  varint and fractional numbers as f32 (f64 only when needed). Tokens are stored
  in original case with a quoted flag and lower-cased per consumer at replay, so
  capture is grammar-independent.
- Writer encodes entries incrementally into a compact buffer instead of holding
  a struct per token, keeping memory bounded when baking huge files in parallel.
- New headless bake mode (-bake) precompiles a scenario and all its includes into
  twins on a thread pool, with no window/renderer/scene; each file is tokenised in
  isolation and baked exactly once.
- Fix stack overflow on files with long runs of consecutive includes by handling
  include directives iteratively instead of recursively (also hardens the normal
  text load).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

EU07.cpp

@@ -20,6 +20,7 @@ Stele, firleju, szociu, hunter, ZiomalCl, OLI_EU and others
 
 #include "application/application.h"
 #include "utilities/Logs.h"
+#include "scene/scenerybinary.h"
 #include <cstdlib>
 #ifdef WITHDUMPGEN
 #ifdef _WIN32
@@ -98,6 +99,12 @@ int main(int argc, char *argv[])
 		int dynamic = std::stoi(std::string(argv[5]));
 		export_e3d_standalone(in, out, flags, dynamic);
 	}
+	// headless bake: precompile a scenery (and all its includes) into binary twins with
+	// no window, renderer or simulation. usage: eu07 -bake <sceneryfile relative to scenery/>
+	else if (argc >= 3 && std::string(argv[1]) == "-bake")
+	{
+		scene::scenerybinary_bake_headless(argv[2], Global.asCurrentSceneryPath, Global.bLoadTraction);
+	}
 	else
 	{
 		try