Track completion history, candidates and async directory results by the active
SSH/WSL connection, and restore the parent shell when the connection returns.
Use shared ownership rules in both UI adapters and report expanded arguments
from shell execution hooks. Preserve user PSReadLine prediction settings.
Add regression coverage for context transitions, stale results and actual
Windows ConPTY transport. Validate native SSH, WSL, local PowerShell and SSH
from PowerShell, including cross-environment negatives and native predictions.
History deletion and migration remain outside this change.