feat: 블록체인(chain) 통합 및 내부 API 추가

- internal/chain 패키지 추가 (client, handler, service, repository, model)
- 체인 연동 엔드포인트: 지갑 조회, 잔액, 자산, 인벤토리, 마켓 등
- 관리자 전용 체인 엔드포인트: 민팅, 보상, 템플릿 등록
- 게임 서버용 내부 API (/api/internal/chain/*) + ServerAuth 미들웨어
- 회원가입 시 블록체인 월렛 자동 생성
- 체인 관련 환경변수 및 InternalAPIKey 설정 추가

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

go.mod

@@ -2,31 +2,46 @@ module a301_server
 
 go 1.25
 
+require (
+	github.com/gofiber/fiber/v2 v2.52.11
+	github.com/golang-jwt/jwt/v5 v5.3.1
+	github.com/joho/godotenv v1.5.1
+	github.com/redis/go-redis/v9 v9.18.0
+	github.com/tolelom/tolchain v0.0.0
+	golang.org/x/crypto v0.48.0
+	gorm.io/driver/mysql v1.6.0
+	gorm.io/gorm v1.31.1
+)
+
 require (
 	filippo.io/edwards25519 v1.1.0 // indirect
 	github.com/andybalholm/brotli v1.1.0 // indirect
+	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/cespare/xxhash/v2 v2.3.0 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/go-sql-driver/mysql v1.8.1 // indirect
-	github.com/gofiber/fiber/v2 v2.52.11 // indirect
-	github.com/golang-jwt/jwt/v5 v5.3.1 // indirect
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/jinzhu/inflection v1.0.0 // indirect
 	github.com/jinzhu/now v1.1.5 // indirect
-	github.com/joho/godotenv v1.5.1 // indirect
-	github.com/klauspost/compress v1.17.9 // indirect
+	github.com/klauspost/compress v1.18.0 // indirect
+	github.com/kr/text v0.2.0 // indirect
 	github.com/mattn/go-colorable v0.1.13 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
 	github.com/mattn/go-runewidth v0.0.16 // indirect
-	github.com/redis/go-redis/v9 v9.18.0 // indirect
+	github.com/munnerz/goautoneg v0.0.0-20191010083416-a7dc8b61c822 // indirect
+	github.com/prometheus/client_golang v1.23.2 // indirect
+	github.com/prometheus/client_model v0.6.2 // indirect
+	github.com/prometheus/common v0.66.1 // indirect
+	github.com/prometheus/procfs v0.16.1 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/valyala/bytebufferpool v1.0.0 // indirect
 	github.com/valyala/fasthttp v1.51.0 // indirect
 	github.com/valyala/tcplisten v1.0.0 // indirect
 	go.uber.org/atomic v1.11.0 // indirect
-	golang.org/x/crypto v0.48.0 // indirect
+	go.yaml.in/yaml/v2 v2.4.2 // indirect
 	golang.org/x/sys v0.41.0 // indirect
 	golang.org/x/text v0.34.0 // indirect
-	gorm.io/driver/mysql v1.6.0 // indirect
-	gorm.io/gorm v1.31.1 // indirect
+	google.golang.org/protobuf v1.36.8 // indirect
 )
+
+replace github.com/tolelom/tolchain => ../tolchain