fix(redis): confirm before Refresh or leaving a dirty string key #873

Summary

String key editor has no dirty tracking / UnsavedWorkRegistry. Breadcrumb Refresh remounts RedisKeyEditor via ValueKey(…_refreshEpoch) and reloads from the server. Crumb navigation to the keys list also drops in-progress text. Same class as Mongo #782 / Refresh follow-up.

Repro

1. Open a string key, edit the value, do not Save.
2. Click Refresh, or the keys crumb.

Expected: discard dialog. Actual: text is gone.

Scope

• Track dirty string (and other in-place editors if they share the same remount).
• Confirm before Refresh remount and before _navigateToKeys / leaving the editor.
• Honor session read-only (already gates Save).

Out of scope

• Binary / stream keys (already non-SET).
• KEEPTTL path (fix(redis): SET Save must keep existing TTL (KEEPTTL) #811).