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/shared/src/moderator.ts

@@ -0,0 +1,28 @@
+import type { Color, PieceType } from './types.js';
+
+export type ModeratorText =
+  | 'no_such_piece'
+  | 'no_legal_moves'
+  | 'wont_help'
+  | 'illegal_move'
+  | 'white_moved' | 'black_moved'
+  | 'white_moved_captured' | 'black_moved_captured'
+  | 'white_moved_captured_ep' | 'black_moved_captured_ep'
+  | 'white_castled_kingside' | 'white_castled_queenside'
+  | 'black_castled_kingside' | 'black_castled_queenside'
+  | 'white_in_check' | 'black_in_check'
+  | 'white_promoted' | 'black_promoted'
+  | 'white_checkmate' | 'black_checkmate'
+  | 'stalemate' | 'draw_insufficient' | 'draw_fifty' | 'draw_threefold'
+  | 'white_resigned' | 'black_resigned'
+  | 'draw_agreed' | 'game_abandoned';
+
+export type Audience = Color | 'both';
+
+export interface Announcement {
+  ply: number;
+  text: ModeratorText;
+  audience: Audience;
+  payload?: { promotedTo?: PieceType };
+  at: number;
+}