Fizlet 0.5.0

The page profile for heroes and interactive diagrams (the Fizlet factory's layer budgets, "Page interactions"; lab audit docs/audit-heroes.md: idle CPU while visible was the hero's real cost).

• kernel: settle option. Systems call engine.busy() while something moves; after settle seconds without it the engine sleeps (paused: ["settled"], no requestAnimationFrame at all) until engine.wake(), its controls input (keys, pointer down/move) or start(). Not a pause: pause hooks don't run. fps option: a frame-rate cap on the shared clock. Both off by default; kernel 3106 → 3275 B gzip.
• slot: waits for an idle main thread once near the viewport (idle, default 1000 ms). A tap on the slot before the scene is up loads it at once and reaches mount(stage, slot, first) as { x, y, at }, never as the stale PointerEvent (the DOM VIRUS hero threw on setPointerCapture for exactly this). Slot 1767 B gzip.
• Page build budget: kernel + slot + input + fx ≤ 7 KB gzip (6,792 B), leaving a 10 KB hero chunk ≥ 3 KB for the scene. tests/page.test.mjs fails if a game-only brick gets into it.
• Tests: settle (sleeps, no rAF, no pause hooks, wake and start), fps cap (30 on a 60 Hz clock), and in Chromium the idle wait, the first tap and a key waking a settled engine.