Add a `connect_timeout_secs` field to ConnectionConfig that allows users
to configure the database connection timeout per connection (1-300s,
default 5s). Previously all connections used a hardcoded 5-second timeout.
- Add connect_timeout_secs field with serde default and clamp logic
- Add parse_connect_timeout_with_fallback to honor URL params over config
- Pass user-configured timeout to all drivers (MySQL, Postgres, Redis,
MongoDB, ClickHouse, SQL Server, Elasticsearch) and TCP probe
- Add UI input in connection dialog SSH tab
- Add i18n keys for en/zh-CN/es
t8y2