* fix(ai-vault): replace scanner internals with actionable panel copy
Agent Session History painted the scanner's supervision errors verbatim:
"AI Vault service restart circuit is open." and "AI Vault service timed
out after 130000ms." Neither tells a user what happened or what to do.
Add a shared mapper that rewrites the supervision family into copy tied
to an action, passing anything unrecognized through so scanner-authored
messages (host name, remote path, cap) keep their own wording. It also
strips Electron's `Error invoking remote method` wrapper, which this
path never handled. Applied at both surfaces the panel paints: the local
leg's scan-issue row and the thrown-rejection banner. Humanizing in main
covers remote clients too; the raw text moves to the main log.
Also make "Refresh to try again" true. The relay path lets a forced
refresh reopen the restart circuit, but on the local path `force` stopped
at the cache layer and never reached the supervisor, so the refresh
button was inert for the full 60s fault window.
The client file sat at 299/300 lines, so extract the child-listener and
init-frame wiring into `attachAiVaultServiceChild`, next to the
ready-waiter and retirement helpers it belongs with, rather than bumping
the max-lines ceiling.
* fix(ai-vault): humanize runtime scanner errors
* fix(ai-vault): preserve runtime error metadata
* fix(ai-vault): normalize wrapped scan errors
* fix(ai-vault): preserve non-scanner relay errors
* fix(ai-vault): make forced retries cancel backoff
