feat: implement and deploy blind_chess MVP

- pnpm workspace: shared/server/client packages
- Server: Fastify+ws, chess.js, FSM (touch-move + hierarchy),
  per-player view filter, zod validation, rate limiting, grace-window
  disconnect handling
- Client: Svelte 5 + Vite, click-to-move board, moderator panel,
  promotion/draw dialogs
- Shared: protocol types, ModeratorText enum, geometricMoves helper
  (provably zero opponent-info leak)
- 43 tests pass (21 shared, 22 server incl. 4 real-WS integration)
- Deploy: CT 690 on node-241 (192.168.0.245), systemd-managed,
  Caddy block for chess.sethpc.xyz
- Live at https://chess.sethpc.xyz

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

packages/client/src/App.svelte

@@ -0,0 +1,35 @@
+<script lang="ts">
+  import Landing from './lib/Landing.svelte';
+  import Game from './lib/Game.svelte';
+
+  let route: { name: 'landing' } | { name: 'game'; id: string } = $state({ name: 'landing' });
+
+  function parseHash() {
+    // Support both pathname-based (joinUrl: /g/<id>) and hash-based (#/g/<id>) routes.
+    const hash = location.hash || '';
+    const hashMatch = hash.match(/^#\/g\/([a-z0-9]{8})$/);
+    if (hashMatch) {
+      route = { name: 'game', id: hashMatch[1]! };
+      return;
+    }
+    const pathMatch = location.pathname.match(/^\/g\/([a-z0-9]{8})\/?$/);
+    if (pathMatch) {
+      route = { name: 'game', id: pathMatch[1]! };
+      return;
+    }
+    route = { name: 'landing' };
+  }
+
+  $effect(() => {
+    parseHash();
+    const handler = () => parseHash();
+    window.addEventListener('hashchange', handler);
+    return () => window.removeEventListener('hashchange', handler);
+  });
+</script>
+
+{#if route.name === 'landing'}
+  <Landing />
+{:else}
+  <Game gameId={route.id} />
+{/if}