Pause before connecting over Boundary tunnels

[rolandwalker]

Description

The Boundary tunnels might not be quite ready at creation time, as there are some nondeterministic connection errors:

$ mycli boundary_alias
Connection to server lost. If this error persists, it may be a mismatch between the server and client SSL configuration. To troubleshoot the issue, try --ssl-mode=off or --ssl-mode=on.
(2013, 'Lost connection to MySQL server during query')

$ mycli boundary_alias
(2003, "Can't connect to MySQL server on '127.0.0.1' ([Errno 22] Invalid argument)")

$ mycli boundary_alias
employees> /* worked! */

0.25 seconds might be too long to pause. Having any pause at all is regrettable, especially for a user driving mycli in a script.

Incidentally update the changelog for a patch release.

Checklist

• I added this contribution to the changelog.md file.
• I added my name to the AUTHORS file (or it's already there).
• To lint and format the code, I ran

  uv run ruff check && uv run ruff format && uv run mypy --install-types .