The terminal's resilience screen tests where snapshots go with `t`: reached or not, in words, never a key, as MCP `backups_test` does #7297

For: the owner who wants to know the off-box backups actually work, from the terminal. Never lost means checking it is one key.

testDestination (src/actions/destination.ts) is reached from the Backups page's Test button and MCP backups_test. The terminal's resilience screen (src/tui/screens/resilience.ts) cannot test.

Done:

• [ ] t, for a forge admin who is a person, tests the destination in effect and shows reached or not with the page's words.
• [ ] With no destination set it says so, and does not call out.
• [ ] The answer and the frame never carry a key.
• [ ] A new test/tui-backups-test.test.ts: a reachable fake store reads reached, an unreachable one reads its reason, a non-admin is not offered t.

Files: src/tui/screens/resilience.ts, one test. Risk: low.

Parked by the crew: the check stayed red through 2 automatic tries (pull #7312 closed). Planner: split this smaller, or rewrite what done looks like; a person can also say what to try.