chore(deploy): 数据库与各服务增加资源限制和优雅关闭保护

- postgres 增加 mem_limit/cpus/shm_size/stop_grace_period 与 PG
  性能参数(shared_buffers 等,env 可覆盖);backend/web 增加
  内存/CPU 限额与更长的优雅关闭宽限(生产与开发编排同步)
- ubuntu-deploy.sh 增加部署前磁盘空间预检,防止备份或迁移
  中途磁盘写满
- .env.server.example 补充资源变量;文档补充容器资源限制说明

docker-compose.dev.yml

@@ -16,8 +16,20 @@ services:
         "pg_stat_statements.track=all",
         "-c",
         "log_min_duration_statement=${POSTGRES_LOG_MIN_DURATION_STATEMENT_MS:-500}",
+        "-c",
+        "shared_buffers=${POSTGRES_SHARED_BUFFERS:-256MB}",
+        "-c",
+        "effective_cache_size=${POSTGRES_EFFECTIVE_CACHE_SIZE:-1GB}",
+        "-c",
+        "work_mem=${POSTGRES_WORK_MEM:-8MB}",
+        "-c",
+        "maintenance_work_mem=${POSTGRES_MAINTENANCE_WORK_MEM:-128MB}",
       ]
     restart: unless-stopped
+    mem_limit: ${POSTGRES_MEM_LIMIT:-1g}
+    cpus: ${POSTGRES_CPUS:-2}
+    shm_size: 512mb
+    stop_grace_period: 60s
     logging: *json-log-rotation
     environment:
       TZ: ${TZ:-Asia/Shanghai}