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/controller/admin/chain_controller.go

@@ -0,0 +1,71 @@
+package admin
+
+import (
+	"github.com/assimon/luuu/model/data"
+	"github.com/labstack/echo/v4"
+)
+
+// UpdateChainRequest is the payload for updating chain settings.
+type UpdateChainRequest struct {
+	Enabled          *bool   `json:"enabled" example:"true"`
+	MinConfirmations *int    `json:"min_confirmations" example:"20"`
+	ScanIntervalSec  *int    `json:"scan_interval_sec" example:"5"`
+	DisplayName      *string `json:"display_name" example:"Tron"`
+}
+
+// ListChains returns the chains table (tron/ethereum/solana seeded; new
+// networks like bsc/polygon inserted manually once supported).
+// @Summary      List chains
+// @Description  Returns all supported blockchain networks
+// @Tags         Admin Chains
+// @Security     AdminJWT
+// @Produce      json
+// @Success      200 {object} response.ApiResponse{data=[]mdb.Chain}
+// @Failure      400 {object} response.ApiResponse
+// @Router       /admin/api/v1/chains [get]
+func (c *BaseAdminController) ListChains(ctx echo.Context) error {
+	rows, err := data.ListChains()
+	if err != nil {
+		return c.FailJson(ctx, err)
+	}
+	return c.SucJson(ctx, rows)
+}
+
+// UpdateChain toggles enabled / tweaks scan params. Scanners re-read the
+// chains table on every poll tick, so changes take effect within one
+// cycle without a restart.
+// @Summary      Update chain
+// @Description  Toggle enabled / tweak scan params for a chain
+// @Tags         Admin Chains
+// @Security     AdminJWT
+// @Accept       json
+// @Produce      json
+// @Param        network path string true "Network name (e.g. tron, ethereum, solana)"
+// @Param        request body admin.UpdateChainRequest true "Chain settings"
+// @Success      200 {object} response.ApiResponse
+// @Failure      400 {object} response.ApiResponse
+// @Router       /admin/api/v1/chains/{network} [patch]
+func (c *BaseAdminController) UpdateChain(ctx echo.Context) error {
+	network := ctx.Param("network")
+	req := new(UpdateChainRequest)
+	if err := ctx.Bind(req); err != nil {
+		return c.FailJson(ctx, err)
+	}
+	fields := map[string]interface{}{}
+	if req.Enabled != nil {
+		fields["enabled"] = *req.Enabled
+	}
+	if req.MinConfirmations != nil {
+		fields["min_confirmations"] = *req.MinConfirmations
+	}
+	if req.ScanIntervalSec != nil {
+		fields["scan_interval_sec"] = *req.ScanIntervalSec
+	}
+	if req.DisplayName != nil {
+		fields["display_name"] = *req.DisplayName
+	}
+	if err := data.UpdateChainFields(network, fields); err != nil {
+		return c.FailJson(ctx, err)
+	}
+	return c.SucJson(ctx, nil)
+}