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/lib/ModeratorPanel.svelte

@@ -0,0 +1,79 @@
+<script lang="ts">
+  import type { Announcement, Color } from '@blind-chess/shared';
+  import { moderatorText } from './moderator-strings.js';
+
+  interface Props {
+    announcements: Announcement[];
+    you: Color;
+  }
+  let { announcements, you }: Props = $props();
+
+  // Show only entries this viewer is allowed to see.
+  const visible = $derived(
+    announcements.filter((a) => a.audience === 'both' || a.audience === you),
+  );
+
+  let scrollEl: HTMLDivElement | null = $state(null);
+  $effect(() => {
+    void visible.length;
+    if (scrollEl) scrollEl.scrollTop = scrollEl.scrollHeight;
+  });
+</script>
+
+<div class="panel">
+  <header>Moderator</header>
+  <div class="log" bind:this={scrollEl}>
+    {#each visible as a, i (i)}
+      <div class="entry" class:err={a.text === 'illegal_move' || a.text === 'no_such_piece' || a.text === 'no_legal_moves' || a.text === 'wont_help'}>
+        <span class="ply">{a.ply > 0 ? `#${a.ply}` : ''}</span>
+        <span class="text">{moderatorText(a.text, a.payload)}</span>
+      </div>
+    {:else}
+      <div class="empty muted">The moderator is silent.</div>
+    {/each}
+  </div>
+</div>
+
+<style>
+  .panel {
+    background: var(--panel);
+    border: 1px solid var(--border);
+    border-radius: 8px;
+    display: flex;
+    flex-direction: column;
+    height: 100%;
+    min-height: 200px;
+  }
+  header {
+    padding: 10px 14px;
+    font-size: 13px;
+    font-weight: 600;
+    color: var(--text-dim);
+    text-transform: uppercase;
+    letter-spacing: 0.08em;
+    border-bottom: 1px solid var(--border);
+  }
+  .log {
+    padding: 8px 14px;
+    flex: 1;
+    overflow-y: auto;
+    font-size: 14px;
+    line-height: 1.5;
+  }
+  .entry {
+    padding: 4px 0;
+    display: flex;
+    gap: 8px;
+    border-bottom: 1px dashed rgba(255,255,255,0.05);
+  }
+  .entry:last-child { border-bottom: none; }
+  .entry.err .text { color: #f87171; }
+  .ply {
+    color: var(--text-dim);
+    font-family: ui-monospace, monospace;
+    font-size: 12px;
+    flex-shrink: 0;
+    width: 32px;
+  }
+  .empty { padding: 6px 0; font-style: italic; }
+</style>