be7f06e163
Mirror the screen into browser history via SvelteKit shallow routing (pushState/replaceState with page.state) so Back/Forward move between screens while the URL stays at /game/. Overlays (game, lobby-create) push; lobby/login replace. A popstate→page.state effect syncs the store back without re-pushing (no loop); the boot stamp puts a restored overlay above the load entry so Back falls through to lobby. In-game view switches never touch history. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>