feat: add admin panel with multi-chain support and notification system

- Add full admin REST API: auth, API keys, chains, chain tokens, wallets,
  orders, RPC nodes, settings, dashboard stats, notifications
- Add JWT-based admin authentication and API key auth middleware
- Add multi-chain listeners: BSC, ETH, Polygon, Plasma, EVM WebSocket
- Add RPC node health check job with automatic failover
- Add Telegram notification channel for order events
- Add installer for first-run database initialization
- Add new DB models: admin_user, api_key, chain, chain_token,
  rpc_node, settings, notification_channel
- Add order statistics aggregation (daily/monthly/by-chain)
- Serve built admin SPA from embedded www/ assets
- Add comprehensive test coverage for all new features

src/model/data/wallet_address_data_test.go

@@ -0,0 +1,83 @@
+package data
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/assimon/luuu/internal/testutil"
+	"github.com/assimon/luuu/model/dao"
+	"github.com/assimon/luuu/model/mdb"
+)
+
+func TestAddWalletAddressWithNetworkNormalizesEvmAddressToLowercase(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	input := "0xA1B2c3D4e5F60718293aBcDeF001122334455667"
+	row, err := AddWalletAddressWithNetwork(mdb.NetworkEthereum, input)
+	if err != nil {
+		t.Fatalf("add wallet: %v", err)
+	}
+	if row.Address != strings.ToLower(input) {
+		t.Fatalf("wallet address = %q, want %q", row.Address, strings.ToLower(input))
+	}
+
+	loaded, err := GetWalletAddressByNetworkAndAddress(mdb.NetworkEthereum, strings.ToUpper(input))
+	if err != nil {
+		t.Fatalf("load wallet by mixed-case address: %v", err)
+	}
+	if loaded.ID == 0 {
+		t.Fatal("expected to find wallet by mixed-case query")
+	}
+	if loaded.Address != strings.ToLower(input) {
+		t.Fatalf("stored wallet address = %q, want lowercase", loaded.Address)
+	}
+}
+
+func TestGetAvailableWalletAddressByNetworkReturnsLowercaseForEvm(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	mixed := "0xA1B2c3D4e5F60718293aBcDeF001122334455667"
+	if err := dao.Mdb.Create(&mdb.WalletAddress{
+		Network: mdb.NetworkEthereum,
+		Address: mixed,
+		Status:  mdb.TokenStatusEnable,
+	}).Error; err != nil {
+		t.Fatalf("seed mixed-case wallet: %v", err)
+	}
+
+	rows, err := GetAvailableWalletAddressByNetwork("Ethereum")
+	if err != nil {
+		t.Fatalf("list wallets: %v", err)
+	}
+	if len(rows) != 1 {
+		t.Fatalf("wallet count = %d, want 1", len(rows))
+	}
+	if rows[0].Address != strings.ToLower(mixed) {
+		t.Fatalf("listed wallet address = %q, want %q", rows[0].Address, strings.ToLower(mixed))
+	}
+}
+
+func TestAddWalletAddressWithNetworkKeepsOriginalCaseForNonEvm(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	tronAddress := "TCaseSensitiveTronAddress001"
+	tronRow, err := AddWalletAddressWithNetwork(mdb.NetworkTron, tronAddress)
+	if err != nil {
+		t.Fatalf("add tron wallet: %v", err)
+	}
+	if tronRow.Address != tronAddress {
+		t.Fatalf("tron wallet address = %q, want %q", tronRow.Address, tronAddress)
+	}
+
+	solAddress := "SoLAnACaseSensitiveAddress111111111111111111"
+	solRow, err := AddWalletAddressWithNetwork(mdb.NetworkSolana, solAddress)
+	if err != nil {
+		t.Fatalf("add solana wallet: %v", err)
+	}
+	if solRow.Address != solAddress {
+		t.Fatalf("solana wallet address = %q, want %q", solRow.Address, solAddress)
+	}
+}