fix: gofmt alignment in http3 server and surface errors in main.go demo

- gofmt the x509.Certificate struct literal in generateTLSConfig
- grpcSample() now checks and prints errors from http3.ServerRun and
  http3.ClientRun instead of silently discarding them (e.g. port
  conflicts previously failed with no output)

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

lib/grpc/http3/server.go

@@ -33,11 +33,11 @@ func generateTLSConfig() (*tls.Config, error) {
 		Subject: pkix.Name{
 			Organization: []string{"gRPC HTTP3 Canary"},
 		},
-		NotBefore: time.Now(),
-		NotAfter:  time.Now().Add(365 * 24 * time.Hour),
-		KeyUsage:  x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		NotBefore:   time.Now(),
+		NotAfter:    time.Now().Add(365 * 24 * time.Hour),
+		KeyUsage:    x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
 		ExtKeyUsage: []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
-		DNSNames:  []string{"localhost"},
+		DNSNames:    []string{"localhost"},
 		IPAddresses: []net.IP{net.ParseIP("127.0.0.1"), net.ParseIP("::1")},
 	}
 

lib/main.go

@@ -2,8 +2,7 @@ package main
 
 import (
 	"fmt"
-	"grpccanary/lib/grpc/basic"
-	"grpccanary/lib/jsonexample"
+	"grpccanary/lib/grpc/http3"
 	"time"
 )
 
@@ -11,21 +10,27 @@ var port = ":8080"
 
 func main() {
 	// 1단계: JSON 파싱 예제 실행
-	jsonexample.JsonParsingExample()
+	// jsonexample.JsonParsingExample()
 
 	// 3단계: gRPC 통신 예제 실행 (필요 시 주석 제거하여 활성화 가능)
-	// grpcSample()
+	grpcSample()
 }
 
 func grpcSample() {
 	fmt.Println("--- starting gRPC IoT Simulation ---")
 
 	// 1. gRPC 서버를 백그라운드 고루틴으로 구동
-	go basic.ServerRun(port)
+	go func() {
+		if _, _, err := http3.ServerRun(port); err != nil {
+			fmt.Println("ServerRun error:", err)
+		}
+	}()
 
 	// 2. 서버 포트가 바인딩되어 통신 대기 상태에 들어갈 시간을 일시적으로 보장
 	time.Sleep(100 * time.Millisecond)
 
 	// 3. gRPC 클라이언트를 구동하여 원격 프로시저(RPC) 기동 시뮬레이션 집행
-	basic.ClientRun(port)
+	if err := http3.ClientRun(port); err != nil {
+		fmt.Println("ClientRun error:", err)
+	}
 }