fix(P.3.8): use math.floor() for %d format in frame-30 CI trace

units[1].x/y are floats after movement; %d requires integers in Lua 5.4.
Caused update hook error on frame 30, silencing the position trace.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

init.lua

@@ -120,7 +120,7 @@ function update(ctx, dt)
     -- Position trace für smoke-Assert (frame 30 — units sollten sich bewegt haben)
     if frames == 30 and os.getenv("SPOREL_CI") == "1" then
         engine.print(string.format("rts-prototype: frame 30 unit[1] pos=(%d,%d)",
-            units[1].x, units[1].y))
+            math.floor(units[1].x), math.floor(units[1].y)))
     end
 
     -- CI self-exit