feat(deploy): single-image docker-compose and kubernetes install.sh

- multi-stage root Dockerfile (opsx-loki pattern): frontend dist +
  go binary + gh-ost in one alpine image, non-root user, HEALTHCHECK,
  entrypoint warning for missing SECRET_KEY; gin now serves the SPA
  from DIST_DIR (asset/db-logos/favicon passthrough, /api returns JSON
  404, SPA fallback to index.html) - one origin, no CORS surface
- docker-compose.yml rewritten: single service, named data volume,
  no-new-privileges + cap_drop ALL, /health healthcheck, resource
  limits, log rotation; SECRET_KEY required (openssl rand -hex 32),
  JWT_SECRET optional (auto-generated and persisted in prod)
- kubernetes/: install.sh one-command deploy (idempotent secret
  reuse, --nodeport/--ingress flags, rollout wait, backup tips) plus
  namespace/secret/pvc/deployment(single replica + Recreate, probes,
  resource limits, non-root)/service/nodeport/ingress manifests and
  README (sqlite single-writer constraints, snapshot backup)
- docs: README quick-start now has 3 deployment paths; ARCHITECTURE
  ch.14 expanded

single-image runtime verified locally (SPA/assets/api/login coexist
on :9002); full image build left to server (docker hub unreachable
from this machine)

docker-entrypoint.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+# opsxsql 容器入口(参照 opsx-loki):
+#   - 生产(DEBUG=false)缺 SECRET_KEY 时告警(AES 加密数据与密钥绑定,换密钥已存密文不可解)
+#   - JWT_SECRET 未显式提供时,后端会在生产模式自动生成随机密钥并持久化到 /app/data
+set -e
+
+if [ "${DEBUG:-false}" != "true" ]; then
+  if [ -z "${SECRET_KEY:-}" ]; then
+    echo "[entrypoint] 警告: 未设置 SECRET_KEY,使用内置默认密钥(AES 加密实例/LDAP 密码)。" >&2
+    echo "[entrypoint] 生产环境建议: export SECRET_KEY=\$(openssl rand -hex 32) 后重建容器;" >&2
+    echo "[entrypoint] 注意: 更换 SECRET_KEY 会导致已加密的实例/LDAP 密码无法解密,请首次部署即固定。" >&2
+  fi
+  if [ -z "${JWT_SECRET:-}" ]; then
+    echo "[entrypoint] 提示: 未设置 JWT_SECRET,生产模式将自动生成随机密钥并持久化到数据卷。" >&2
+  fi
+fi
+
+mkdir -p /app/data
+
+exec ./opsxsql