Add the SQLX CLI integration to the settings page

[openai0229]

What this adds

A CLI 集成 section in 设置 that installs, updates and locates the OtterMind SQLX command line,
imports the datasources Chat2DB already holds, and shows the Skill command an agent needs.

SQLX is a separate product from the chat2db CLI (/api/cli/v1), so it gets its own module and its own
page section instead of extending the existing CLI entry.

Backend

• chat2db-community-sqlx (new module): platform/asset mapping for the official release, version
  parsing from sqlx --version, a process runner, the release installer (download → SHA-256 → extract →
  atomic move, with a managed fallback directory when the official directory is not writable), settings
  storage, and the status service the page polls.
• Credentials never leave the JVM in the clear: the import reads them with
  queryDisplayDataSourceById(id, true) — the decrypted view the connection path itself uses — and sends
  them to the SQLX child process on stdin. They do not appear in argv, on disk, in the renderer, or in
  logs. The status endpoint never returns a credential.
• chat2db-community-tools: the SqlxBridge contract plus SqlxStatus and SqlxDatasourceState, so
  the JCEF shell reaches the bridge without depending on a domain or storage module.
• chat2db-community-jcef: eight handlers (get-sqlx-status, install-sqlx, update-sqlx,
  check-sqlx-update, cancel-sqlx-operation, set-sqlx-binary, import-sqlx-datasources,
  get-sqlx-datasource-states) and a boundary test that fails if a handler imports an implementation
  package.
• chat2db-community-start: registers the bridge before Spring starts and attaches the datasource
  reader after app.run, so the page never sees a missing bridge.
• SqlxConnectionMapping reaches the eight engines added for the next SQLX release — Presto, Hive,
  Kylin, XuguDB, Db2, Informix (which Chat2DB spells INFOMIX), SUNDB and GBase 8s — instead of skipping
  them as unsupported. Snowflake, Oscar, Elasticsearch, BigQuery and Redshift stay unsupported and keep
  reporting their reason.

Page

Version line with the update check, one adaptive action button (install / update / check), a redetect that
stays visible long enough to be seen, the executable path, a datasource table with a status column
(已导入 / 未导入 / 暂不支持 / 信息不完整) where only importable rows can be selected, the import result as an
alert, and the Skill commands with hover copy buttons.

Verification

• mvn -pl :chat2db-community-sqlx -am test — 41 tests, including the engine mapping for the new types,
  the datasource reader that must use the decrypted view, and the release installer.
• yarn test:sqlx-setting, yarn test:settings-layout, yarn test:i18n, yarn test:community-boundary,
  eslint on the changed files, and yarn build:web:community.
• Exercised by hand in the desktop app against a real installation, a self-update, and an import of a
  MySQL datasource that then answered a query through sqlx.