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/service/task_tron_test.go

@@ -0,0 +1,92 @@
+package service
+
+import (
+	"testing"
+
+	"github.com/assimon/luuu/config"
+	"github.com/assimon/luuu/internal/testutil"
+	"github.com/assimon/luuu/model/dao"
+	"github.com/assimon/luuu/model/mdb"
+)
+
+// TestResolveTronNode_NoRow verifies that resolveTronNode falls back to the
+// hard-coded default when the rpc_nodes table has no TRON row.
+func TestResolveTronNode_NoRow(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	config.TRON_GRID_API_KEY = "fallback-key"
+
+	gotURL, gotKey := resolveTronNode()
+	if gotURL != tronNodeDefault {
+		t.Errorf("url = %q, want %q", gotURL, tronNodeDefault)
+	}
+	if gotKey != "fallback-key" {
+		t.Errorf("apiKey = %q, want \"fallback-key\"", gotKey)
+	}
+}
+
+// TestResolveTronNode_WithRow verifies that resolveTronNode uses the DB row
+// when an enabled TRON HTTP node is present.
+func TestResolveTronNode_WithRow(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	config.TRON_GRID_API_KEY = "fallback-key"
+
+	// Insert an enabled TRON http node.
+	node := &mdb.RpcNode{
+		Network: mdb.NetworkTron,
+		Url:     "https://custom-tron.example.com",
+		Type:    mdb.RpcNodeTypeHttp,
+		ApiKey:  "db-api-key",
+		Weight:  1,
+		Enabled: true,
+		Status:  mdb.RpcNodeStatusOk,
+	}
+	if err := dao.Mdb.Create(node).Error; err != nil {
+		t.Fatalf("seed rpc_node: %v", err)
+	}
+
+	gotURL, gotKey := resolveTronNode()
+	if gotURL != "https://custom-tron.example.com" {
+		t.Errorf("url = %q, want https://custom-tron.example.com", gotURL)
+	}
+	if gotKey != "db-api-key" {
+		t.Errorf("apiKey = %q, want \"db-api-key\"", gotKey)
+	}
+}
+
+// TestResolveTronNode_DisabledRow verifies that a disabled row is ignored and
+// the fallback is used.
+func TestResolveTronNode_DisabledRow(t *testing.T) {
+	cleanup := testutil.SetupTestDatabases(t)
+	defer cleanup()
+
+	config.TRON_GRID_API_KEY = "fallback-key"
+
+	node := &mdb.RpcNode{
+		Network: mdb.NetworkTron,
+		Url:     "https://disabled-tron.example.com",
+		Type:    mdb.RpcNodeTypeHttp,
+		ApiKey:  "disabled-key",
+		Weight:  1,
+		Enabled: true, // start enabled, then disable below
+		Status:  mdb.RpcNodeStatusOk,
+	}
+	if err := dao.Mdb.Create(node).Error; err != nil {
+		t.Fatalf("seed rpc_node: %v", err)
+	}
+	// Explicitly disable — GORM does not save bool zero-value on Create.
+	if err := dao.Mdb.Model(node).Update("enabled", false).Error; err != nil {
+		t.Fatalf("disable rpc_node: %v", err)
+	}
+
+	gotURL, gotKey := resolveTronNode()
+	if gotURL != tronNodeDefault {
+		t.Errorf("url = %q, want %q (disabled row should be ignored)", gotURL, tronNodeDefault)
+	}
+	if gotKey != "fallback-key" {
+		t.Errorf("apiKey = %q, want \"fallback-key\"", gotKey)
+	}
+}