feat: explorer API, wallet, CCIP scripts, and config refresh

- Backend REST/gateway/track routes, analytics, Blockscout proxy paths.
- Frontend wallet and liquidity surfaces; MetaMask token list alignment.
- Deployment docs, verification scripts, address inventory updates.

Check: go build ./... under backend/ (pass).
Made-with: Cursor

backend/api/rest/stats.go

@@ -3,10 +3,64 @@ package rest
 import (
 	"context"
 	"encoding/json"
+	"fmt"
 	"net/http"
 	"time"
+
+	"github.com/jackc/pgx/v5"
 )
 
+type explorerStats struct {
+	TotalBlocks       int64 `json:"total_blocks"`
+	TotalTransactions int64 `json:"total_transactions"`
+	TotalAddresses    int64 `json:"total_addresses"`
+	LatestBlock       int64 `json:"latest_block"`
+}
+
+type statsQueryFunc func(ctx context.Context, sql string, args ...any) pgx.Row
+
+func loadExplorerStats(ctx context.Context, chainID int, queryRow statsQueryFunc) (explorerStats, error) {
+	var stats explorerStats
+
+	if err := queryRow(ctx,
+		`SELECT COUNT(*) FROM blocks WHERE chain_id = $1`,
+		chainID,
+	).Scan(&stats.TotalBlocks); err != nil {
+		return explorerStats{}, fmt.Errorf("query total blocks: %w", err)
+	}
+
+	if err := queryRow(ctx,
+		`SELECT COUNT(*) FROM transactions WHERE chain_id = $1`,
+		chainID,
+	).Scan(&stats.TotalTransactions); err != nil {
+		return explorerStats{}, fmt.Errorf("query total transactions: %w", err)
+	}
+
+	if err := queryRow(ctx,
+		`SELECT COUNT(*) FROM (
+			SELECT from_address AS address
+			FROM transactions
+			WHERE chain_id = $1 AND from_address IS NOT NULL AND from_address <> ''
+			UNION
+			SELECT to_address AS address
+			FROM transactions
+			WHERE chain_id = $1 AND to_address IS NOT NULL AND to_address <> ''
+		) unique_addresses`,
+		chainID,
+	).Scan(&stats.TotalAddresses); err != nil {
+		return explorerStats{}, fmt.Errorf("query total addresses: %w", err)
+	}
+
+	if err := queryRow(ctx,
+		`SELECT COALESCE(MAX(number), 0) FROM blocks WHERE chain_id = $1`,
+		chainID,
+	).Scan(&stats.LatestBlock); err != nil {
+		return explorerStats{}, fmt.Errorf("query latest block: %w", err)
+	}
+
+	return stats, nil
+}
+
 // handleStats handles GET /api/v2/stats
 func (s *Server) handleStats(w http.ResponseWriter, r *http.Request) {
 	if r.Method != http.MethodGet {
@@ -20,43 +74,12 @@ func (s *Server) handleStats(w http.ResponseWriter, r *http.Request) {
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
 
-	// Get total blocks
-	var totalBlocks int64
-	err := s.db.QueryRow(ctx,
-		`SELECT COUNT(*) FROM blocks WHERE chain_id = $1`,
-		s.chainID,
-	).Scan(&totalBlocks)
+	stats, err := loadExplorerStats(ctx, s.chainID, s.db.QueryRow)
 	if err != nil {
-		totalBlocks = 0
-	}
-
-	// Get total transactions
-	var totalTransactions int64
-	err = s.db.QueryRow(ctx,
-		`SELECT COUNT(*) FROM transactions WHERE chain_id = $1`,
-		s.chainID,
-	).Scan(&totalTransactions)
-	if err != nil {
-		totalTransactions = 0
-	}
-
-	// Get total addresses
-	var totalAddresses int64
-	err = s.db.QueryRow(ctx,
-		`SELECT COUNT(DISTINCT from_address) + COUNT(DISTINCT to_address) FROM transactions WHERE chain_id = $1`,
-		s.chainID,
-	).Scan(&totalAddresses)
-	if err != nil {
-		totalAddresses = 0
-	}
-
-	stats := map[string]interface{}{
-		"total_blocks":       totalBlocks,
-		"total_transactions": totalTransactions,
-		"total_addresses":    totalAddresses,
+		writeError(w, http.StatusServiceUnavailable, "service_unavailable", "explorer stats are temporarily unavailable")
+		return
 	}
 
 	w.Header().Set("Content-Type", "application/json")
 	json.NewEncoder(w).Encode(stats)
 }
-