Federation host meets Svelte 5 — three lessons we couldn't find in the docs

augment-it now has a real Module Federation host. The shell at :3000 mounts the record-collector remote at :3002, and the architecture has a federation boundary for the first time. Getting there meant fighting three subtle Svelte-5-plus-MF interactions that the official docs gloss over: shared-singleton factories that wouldn't register, $effect_orphan errors from cross-runtime mounts, and component-scoped CSS that quietly disappears across federation chunk boundaries. Each one has a fix worth keeping.