seo: add og:image, Twitter Cards, meta tags

index.html:
- Add og:image with dimensions (1200x630)
- Add Twitter Cards (summary_large_image)

terms.html, privacy.html, sla.html:
- Add meta description
- Add robots, canonical URL
- Add Open Graph tags

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

index.html

@@ -17,8 +17,18 @@
   <meta property="og:url" content="https://hosting.anvil.it.com">
   <meta property="og:title" content="Anvil Hosting - 엔지니어가 관리하는 Linux 서버">
   <meta property="og:description" content="엔지니어가 직접 튜닝한 Linux 서버. 고객의 문제가 해결될 때까지, 우리는 멈추지 않습니다.">
+  <meta property="og:image" content="https://hosting.anvil.it.com/og-image.png">
+  <meta property="og:image:width" content="1200">
+  <meta property="og:image:height" content="630">
+  <meta property="og:image:alt" content="Anvil Hosting - 엔지니어가 관리하는 Linux 서버">
   <meta property="og:locale" content="ko_KR">
 
+  <!-- Twitter Cards -->
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:title" content="Anvil Hosting - 엔지니어가 관리하는 Linux 서버">
+  <meta name="twitter:description" content="엔지니어가 직접 튜닝한 Linux 서버. 고객의 문제가 해결될 때까지, 우리는 멈추지 않습니다.">
+  <meta name="twitter:image" content="https://hosting.anvil.it.com/og-image.png">
+
   <!-- Favicon -->
   <link rel="icon" type="image/svg+xml" href="/favicon.svg">
 

privacy.html

@@ -4,6 +4,17 @@
   <meta charset="utf-8"/>
   <meta content="width=device-width, initial-scale=1.0" name="viewport"/>
   <title>개인정보처리방침 - Anvil Hosting</title>
+  <meta name="description" content="Anvil Hosting 개인정보처리방침. 개인정보를 직접 수집, 저장, 처리하지 않는 최소화 원칙을 따릅니다.">
+  <meta name="robots" content="index, follow">
+  <link rel="canonical" href="https://hosting.anvil.it.com/privacy.html">
+
+  <!-- Open Graph -->
+  <meta property="og:type" content="website">
+  <meta property="og:url" content="https://hosting.anvil.it.com/privacy.html">
+  <meta property="og:title" content="개인정보처리방침 - Anvil Hosting">
+  <meta property="og:description" content="Anvil Hosting 개인정보처리방침. 개인정보 최소화 원칙을 따릅니다.">
+  <meta property="og:locale" content="ko_KR">
+
   <link rel="icon" type="image/svg+xml" href="/favicon.svg">
   <link href="https://fonts.googleapis.com" rel="preconnect"/>
   <link crossorigin="" href="https://fonts.gstatic.com" rel="preconnect"/>

sla.html

@@ -4,6 +4,17 @@
   <meta charset="utf-8"/>
   <meta content="width=device-width, initial-scale=1.0" name="viewport"/>
   <title>서비스 수준 협약 (SLA) - Anvil Hosting</title>
+  <meta name="description" content="Anvil Hosting SLA (서비스 수준 협약). 99.9% 가용성 보장, 장애 대응 시간, 보상 정책을 안내합니다.">
+  <meta name="robots" content="index, follow">
+  <link rel="canonical" href="https://hosting.anvil.it.com/sla.html">
+
+  <!-- Open Graph -->
+  <meta property="og:type" content="website">
+  <meta property="og:url" content="https://hosting.anvil.it.com/sla.html">
+  <meta property="og:title" content="서비스 수준 협약 (SLA) - Anvil Hosting">
+  <meta property="og:description" content="Anvil Hosting SLA. 99.9% 가용성 보장 및 보상 정책을 확인하세요.">
+  <meta property="og:locale" content="ko_KR">
+
   <link rel="icon" type="image/svg+xml" href="/favicon.svg">
   <link href="https://fonts.googleapis.com" rel="preconnect"/>
   <link crossorigin="" href="https://fonts.gstatic.com" rel="preconnect"/>

terms.html

@@ -4,6 +4,17 @@
   <meta charset="utf-8"/>
   <meta content="width=device-width, initial-scale=1.0" name="viewport"/>
   <title>이용약관 - Anvil Hosting</title>
+  <meta name="description" content="Anvil Hosting 이용약관. 서비스 이용 조건, 결제 정책, 금지 행위, 면책 조항 등을 안내합니다.">
+  <meta name="robots" content="index, follow">
+  <link rel="canonical" href="https://hosting.anvil.it.com/terms.html">
+
+  <!-- Open Graph -->
+  <meta property="og:type" content="website">
+  <meta property="og:url" content="https://hosting.anvil.it.com/terms.html">
+  <meta property="og:title" content="이용약관 - Anvil Hosting">
+  <meta property="og:description" content="Anvil Hosting 이용약관. 서비스 이용 조건 및 정책을 확인하세요.">
+  <meta property="og:locale" content="ko_KR">
+
   <link rel="icon" type="image/svg+xml" href="/favicon.svg">
   <link href="https://fonts.googleapis.com" rel="preconnect"/>
   <link crossorigin="" href="https://fonts.gstatic.com" rel="preconnect"/>