[JDBC] Honor DriverManager login timeout

### Describe the enhancement requested

`ArrowFlightJdbcDriver.connect()` does not currently honor the timeout configured through `DriverManager.setLoginTimeout(int)`.

Implement support for the `DriverManager` login timeout:

- Read the value exposed by `DriverManager.getLoginTimeout()` when establishing a connection selected by `DriverManager`.
- Preserve the JDBC semantics of zero: do not impose a login timeout.
- Apply a nonzero timeout to the overall connection attempt, not only the underlying Netty socket connection.
- If the timeout expires, attempt to cancel the connection attempt and throw `SQLTimeoutException`.
- Clean up any allocator, channel, or partially constructed client when the attempt is cancelled or times out.
- Add tests that set and restore the global `DriverManager` timeout and verify timeout enforcement, exception type, and resource cleanup.

This is distinct from #494/#495. The existing `connectTimeoutMs` property configures Netty socket connection attempts and does not consume the timeout configured through `DriverManager`.

Context: #1027 and [the follow-up discussion](https://github.com/apache/arrow-java/pull/1027#issuecomment-5447203124).

Related DataSource work: https://github.com/apache/arrow-java/issues/1267

エントリーポイントは ArrowFlightJdbcDriver.connect(); まず現在の接続経路と既存の connectTimeoutMs の処理を読みます。DriverManager のグローバルなタイムアウトを設定して復元すること、タイムアウトがゼロの場合とゼロ以外の場合の動作、SQLTimeoutException、そして試行全体がキャンセルされた場合またはタイムアウトした場合の allocator、channel、client のクリーンアップを確認するテストカバレッジを追加します。

索引モデルが issue の本文から書いたものです。