Improve security documentation based on Context7 review

aws-ses-setup.md:
- Add SPF records for email authentication
- Add DMARC policy configuration
- Add bounce/complaint handling with SNS
- Add DNS verification commands

n8n-setup-guide.md:
- Use official Docker registry (docker.n8n.io)
- Add N8N_ENCRYPTION_KEY requirement
- Add N8N_ENFORCE_SETTINGS_FILE_PERMISSIONS
- Add N8N_PUBLIC_API_DISABLED option
- Add security headers to nginx config
- Add healthcheck configuration

gitea-setup.md:
- Add password policy (MIN_PASSWORD_LENGTH, PASSWORD_COMPLEXITY)
- Add argon2 password hashing
- Add DISABLE_GIT_HOOKS for security
- Add Docker Secrets configuration
- Add file-based secret management (SECRET_KEY_URI)
- Add REVERSE_PROXY_TRUSTED_PROXIES setting

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

gitea-setup.md

@@ -82,7 +82,12 @@ GITEA_ROOT_URL=https://your-domain.com
 GITEA_HTTP_PORT=3000
 GITEA_SSH_PORT=2222
 
-# Security (automatically generated)
+# Security - 파일 기반 Secret 권장 (환경변수 노출 방지)
+# docker-compose에서 secrets 사용 시:
+# GITEA__security__SECRET_KEY__FILE=/run/secrets/gitea_secret_key
+# GITEA__security__INTERNAL_TOKEN__FILE=/run/secrets/gitea_internal_token
+
+# 환경변수 방식 (개발용)
 GITEA_SECRET_KEY=your_secret_key
 GITEA_INTERNAL_TOKEN=your_internal_token
 
@@ -95,6 +100,75 @@ GITEA_ADMIN_EMAIL=admin@your-domain.com
 GITEA_ADMIN_PASSWORD=secure_password
 ```
 
+### 보안 강화 설정 (app.ini)
+
+프로덕션 환경에서 아래 설정을 `app.ini` 또는 환경변수로 추가:
+
+```ini
+[security]
+; 비밀번호 정책 강화
+MIN_PASSWORD_LENGTH = 10
+PASSWORD_COMPLEXITY = lower,upper,digit
+PASSWORD_HASH_ALGO = argon2
+
+; Git Hooks 비활성화 (보안 강화)
+DISABLE_GIT_HOOKS = true
+
+; 리버스 프록시 신뢰 설정
+REVERSE_PROXY_TRUSTED_PROXIES = 127.0.0.0/8,::1/128
+
+; Secret 파일 기반 관리 (권장)
+SECRET_KEY_URI = file:/etc/gitea/secret_key
+INTERNAL_TOKEN_URI = file:/etc/gitea/internal_token
+
+[service]
+; 회원가입 비활성화 (필요시)
+DISABLE_REGISTRATION = true
+; 로그인 필수
+REQUIRE_SIGNIN_VIEW = true
+; 이메일 비공개 기본값
+DEFAULT_KEEP_EMAIL_PRIVATE = true
+
+[repository.signing]
+; 커밋 서명 설정
+SIGNING_KEY = default
+INITIAL_COMMIT = always
+```
+
+### Docker Secrets 사용 (프로덕션 권장)
+
+```yaml
+# docker-compose.yml
+services:
+  gitea:
+    image: gitea/gitea:latest-rootless
+    environment:
+      - GITEA__security__SECRET_KEY__FILE=/run/secrets/gitea_secret_key
+      - GITEA__security__INTERNAL_TOKEN__FILE=/run/secrets/gitea_internal_token
+      - GITEA__database__PASSWD__FILE=/run/secrets/db_password
+    secrets:
+      - gitea_secret_key
+      - gitea_internal_token
+      - db_password
+
+secrets:
+  gitea_secret_key:
+    file: ./secrets/secret_key
+  gitea_internal_token:
+    file: ./secrets/internal_token
+  db_password:
+    file: ./secrets/db_password
+```
+
+```bash
+# Secret 파일 생성
+mkdir -p secrets
+openssl rand -base64 32 > secrets/secret_key
+openssl rand -base64 32 > secrets/internal_token
+openssl rand -base64 24 > secrets/db_password
+chmod 600 secrets/*
+```
+
 ### Advanced Configuration
 
 For advanced settings, modify: