Phase A/B: fix the game loop and trim the asset payload

Phase A (the hard blocker): the engine now plays a real table live in
the browser via a real per-frame game loop, not just a static render.

Two real, previously-unknown upstream bugs found and fixed along the way:
- RenderDevice::WaitForVSync() unconditionally spawned a real std::thread
  every frame, even on __STANDALONE__ builds - a hard crash under
  Emscripten's single-threaded runtime (0003).
- The desktop game loop is a blocking native while loop with manual
  uSleep throttling, incompatible with a single-threaded WASM main
  thread. Adds Player::EmscriptenStepFrame() (one frame, no internal
  loop) driven by emscripten_set_main_loop, plus new JS-callable
  lifecycle entry points (vpinball_wasm_start/stop/dispose in the new
  src/core/EmscriptenBridge.cpp) that bypass the desktop main()/WinMain()
  chain entirely, since that chain assumes the process runs exactly one
  table to completion then exits (0004).

Verified end-to-end in Chrome: real .vpx load, real shader compilation,
real physics/script engine init, a real running frame loop (observed
advancing), and a clean stop() -> ~Player() teardown mid-session with
no crash or hang.

Phase B: trims the preloaded asset payload from ~51MB to ~11MB by
excluding editor-only bundled example tables and a Monaco code editor
never used by the player runtime, and adds real link-time optimization
(-O2 --closure 1) and --use-preload-cache for repeat visits.

patches/vpinball/0003-renderdevice-vsync-no-thread-emscripten.patch

@@ -0,0 +1,24 @@
+diff --git a/src/renderer/RenderDevice.cpp b/src/renderer/RenderDevice.cpp
+index 1fedf4e..3ccc87f 100644
+--- a/src/renderer/RenderDevice.cpp
++++ b/src/renderer/RenderDevice.cpp
+@@ -2168,10 +2168,19 @@ void RenderDevice::WaitForVSync(const bool asynchronous)
+       m_vsyncCount++;
+       m_presentTimestampReference = usec();
+    };
++#ifndef __EMSCRIPTEN__
+    if (asynchronous)
+       std::thread(lambda).detach(); // Reuse thread ? (we always at most one running at a time)
+    else
+       lambda();
++#else
++   // vpinball-wasm: a single-threaded Emscripten build (no -pthread /
++   // SharedArrayBuffer) cannot construct real std::thread workers - run
++   // synchronously inline instead. This only updates m_vsyncCount/timestamp
++   // bookkeeping (the real vblank-wait branches above are already excluded
++   // for __STANDALONE__ builds), so synchronous execution is equivalent.
++   lambda();
++#endif
+ }
+ 
+ #if defined(ENABLE_BGFX)