Initial commit: Sudoku game with accounts, history, leaderboard, themes and i18n

Node/Express + SQLite backend, vanilla JS frontend, deployed via Docker Compose.

server/db.js

@@ -0,0 +1,38 @@
+const path = require('path');
+const fs = require('fs');
+const Database = require('better-sqlite3');
+
+const dataDir = process.env.DATA_DIR || path.join(__dirname, 'data');
+if (!fs.existsSync(dataDir)) {
+  fs.mkdirSync(dataDir, { recursive: true });
+}
+
+const db = new Database(path.join(dataDir, 'sudoku.db'));
+db.pragma('journal_mode = WAL');
+db.pragma('foreign_keys = ON');
+
+db.exec(`
+  CREATE TABLE IF NOT EXISTS users (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    pseudo TEXT NOT NULL UNIQUE,
+    email TEXT NOT NULL UNIQUE,
+    password_hash TEXT NOT NULL,
+    created_at TEXT NOT NULL DEFAULT (datetime('now'))
+  );
+
+  CREATE TABLE IF NOT EXISTS games (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    user_id INTEGER NOT NULL REFERENCES users(id) ON DELETE CASCADE,
+    difficulty TEXT NOT NULL,
+    time_seconds INTEGER NOT NULL,
+    mistakes INTEGER NOT NULL DEFAULT 0,
+    won INTEGER NOT NULL DEFAULT 0,
+    points INTEGER NOT NULL DEFAULT 0,
+    created_at TEXT NOT NULL DEFAULT (datetime('now'))
+  );
+
+  CREATE INDEX IF NOT EXISTS idx_games_user ON games(user_id);
+  CREATE INDEX IF NOT EXISTS idx_games_diff ON games(difficulty, won, time_seconds);
+`);
+
+module.exports = db;