The linear replay carried each commit's own lineage, so this checkpoint
restores the master-owned surfaces the conflicted regions clobbered and
migrates branch-owned code to master's post-rebase APIs:
- rebuild subprocess-local spawn.ts on master's tree-exit-observer
machinery, keeping the branch's win32 childEnv key semantics and the
Linux zombie-quiescence probe; the zombie test reaps its survivor
directly since a confirmed-absent verdict is a permanent
no-more-signals boundary
- migrate pty-local test stubs to the Inbox-model Agent interface,
Session.create, runnerFailureRules, and the new turn/start payload
- implement the seam's resolveExecutable/spawnTerminal abstracts in the
new pwsh-local and tool-fs-search test fakes
- restore code-runtime, atomic-write, pwsh-local, and app-boot to
master's exact content (the net-zero code-runtime churn is pruned
from this history) and drop rename-detection graft debris
- re-apply the PR's architecture rows and execution-world paragraph,
re-record bilingual pairings, regenerate catalogs, and reconcile the
lockfile
