feat: admin panel - Settings, Categories, Payment Wallets, Seed/Clear data, User Balances

- Settings page: bot token (masked), admin IDs, commission config, WireGuard status
- Categories page: CRUD with product count, delete guard
- Payment Wallets page: commission wallets display, toggle, percentage
- Users page: balance adjustment form (total_balance / bonus_balance) with audit log
- Seed & Reset page: seed demo data (5 users, 10 products, 5 wallets, 5 purchases)
  and clear all data button with confirmation
- Dashboard: flash messages for seed/clear success
- Fixed seed.js: use dynamic IDs instead of hardcoded to avoid FK violations
- Fixed seed.js: clear all tables before seeding to avoid UNIQUE constraints

src/admin/server.js

@@ -10,6 +10,10 @@ import productsRouter from './routes/products.js';
 import walletsRouter from './routes/wallets.js';
 import purchasesRouter from './routes/purchases.js';
 import auditRouter from './routes/audit.js';
+import settingsRouter from './routes/settings.js';
+import categoriesRouter from './routes/categories.js';
+import paymentWalletsRouter from './routes/paymentWallets.js';
+import seedRouter from './routes/seed.js';
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 const app = express();
@@ -37,6 +41,10 @@ app.use('/products', productsRouter);
 app.use('/wallets', walletsRouter);
 app.use('/purchases', purchasesRouter);
 app.use('/audit', auditRouter);
+app.use('/settings', settingsRouter);
+app.use('/categories', categoriesRouter);
+app.use('/payment-wallets', paymentWalletsRouter);
+app.use('/seed', seedRouter);
 
 export function startAdminPanel() {
   const port = parseInt(process.env.ADMIN_PORT || '3001', 10);