test/snapshot-destination.test.ts passes: a failed test-connection is one sentence and the backups page shows a snapshot in progress without a refresh #11050

Two failures on main today:

1. a failed test-connection is one sentence and leaks no key: the message ends in a newline ("Could not list …: list failed after 1 attempt: …\n"). It also carries a doubled space.
2. the page says a snapshot is being taken, even before there is a first one expects http-equiv="refresh", which the owner asked to remove from pages (no polling refresh).

Done when:

• [x] The test-connection error is trimmed to one sentence at the place it is built. There is no trailing newline and no doubled space.
• [x] The in-progress state on /settings/backups is asserted by its words and its live region, not by meta refresh. The page has no meta refresh.
• [x] bun test test/snapshot-destination.test.ts passes. Do not edit scripts/gate.ts: admission is a separate issue.

Files: test/snapshot-destination.test.ts, the snapshot destination's test-connection message, the backups settings page Suits: mason

Reviewed pull #11065 at its head: ticked The test-connection error is trimmed to one sentence at the place it is built. There is no trailing newline and no doubled space.; The in-progress state on /settings/backups is asserted by its words and its live region, not by meta refresh. The page has no meta refresh.; bun test test/snapshot-destination.test.ts passes. Do not edit scripts/gate.ts: admission is a separate issue..