feat: web admin panel + better-sqlite3 migration + Docker fixes

- Added Express.js admin panel on port 3001 (ADMIN_PORT env)
  - Dashboard: stats (users, products, purchases, revenue)
  - Users: list, details, ban/unban toggle
  - Products: CRUD by category
  - Wallets: list with balances
  - Purchases: history with filters
  - Audit log: view audit trail
  - Auth: token-based login with ADMIN_SECRET env var
- Migrated sqlite3 → better-sqlite3
  - database.js: async adapter (runAsync/allAsync/getAsync)
  - purchaseService.js: lastID → lastInsertRowid
  - userService.js: lastID → lastInsertRowid
  - Removed sqlite3 from package.json
- Fixed: dotenv/config import added to index.js
- Fixed: ENCRYPTION_KEY validation (32+ char hex)
- Fixed: Dockerfile multi-stage build (no python needed)
- Fixed: Docker DNS (network: host in build)
- Fixed: docker-compose port 3001, healthcheck on 3001
- Added express, cookie-parser, pino-pretty, better-sqlite3 deps

src/index.js

@@ -1,3 +1,4 @@
+import 'dotenv/config';
 import { runMigrations, cleanUpInvalidForeignKeys } from './migrations/runner.js';
 import './router/routes.js';
 import bot from './context/bot.js';
@@ -71,17 +72,5 @@ process.on('unhandledRejection', (error) => {
 
 logger.info('Bot is running...');
 
-// Health check endpoint for Docker
-import http from 'http';
-const healthServer = http.createServer((req, res) => {
-    if (req.url === '/health') {
-        res.writeHead(200, { 'Content-Type': 'application/json' });
-        res.end(JSON.stringify({ status: 'ok', uptime: process.uptime() }));
-    } else {
-        res.writeHead(404);
-        res.end('Not found');
-    }
-});
-healthServer.listen(3000, () => {
-    logger.info({ port: 3000 }, 'Health check server started');
-});
+import { startAdminPanel } from './admin/server.js';
+startAdminPanel();