feat(kotlin-compose): design system + 33 components + gallery_kt + e2e android emulator + scaffolder fixes

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cpp/functions/gamedev/game_loop.h

@@ -0,0 +1,22 @@
+#pragma once
+
+// game_loop — fixed-timestep game loop (Glenn Fiedler) for SDL3 + WASM.
+// Issue 0072b. Decouples physics/sim (fixed dt) from rendering (interp).
+
+#include <SDL3/SDL.h>
+
+namespace fn::game {
+
+struct LoopCfg {
+    float fixed_dt = 1.0f / 60.0f;
+    int max_steps_per_frame = 5;
+    void (*on_fixed_update)(void* user, float dt) = nullptr;
+    void (*on_render)(void* user, float interp) = nullptr;
+    bool (*should_quit)(void* user) = nullptr;  // optional poll
+    void* user = nullptr;
+};
+
+// Blocking on desktop. On WASM uses emscripten_set_main_loop and returns immediately.
+void loop_run(SDL_Window* win, const LoopCfg& cfg);
+
+}  // namespace fn::game