feat(deploy): harden Studio persistence and Compose bootstrap

[Aias00]

Summary

Consolidates #978, #957, and #991 into Studio deployment and persistence setup.

• Keep the default MySQL schema DDL-only and prevent demo records from being seeded in production.
• Run idempotent MySQL schema upgrades through a Compose migration job before backend startup.
• Add PostgreSQL 16+ persistence support, equivalent schema, integration coverage, and deployment documentation.
• Document the required RocketMQ Compose startup and network readiness check before Studio starts.

Verification

• JAVA_HOME=$(/usr/libexec/java_home -v 21) mvn -q -DskipTests compile
• docker compose -f deploy/rocketmq/docker-compose.yml config
• docker compose -f deploy/docker-compose.yml config
• git diff --check origin/rocketmq-studio...HEAD
• PostgreSqlSettingsRepositoryIntegrationTest remains blocked locally because the Docker Java client exposes API 1.32 while the Docker daemon requires API 1.40.

Closes #973
Closes #974
Closes #956
Closes #988

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[lizhimins]

Closing this one after review: we decided not to introduce a PostgreSQL persistence branch — the backend stays MySQL-only for broader applicability. The compose migration ideas may be revisited separately on top of the MySQL schema. Thanks for the effort!

评审后决定不引入 PostgreSQL 持久化分支，后端统一保持 MySQL 以更具普适性。Compose 迁移相关想法后续可在 MySQL schema 基础上单独讨论。感谢贡献！