The linear replay carried old-lineage content over parent-owned files;
this checkpoint restores them and adapts the branch to the parent's
post-rebase seam:
- restore all pty/lsp/subprocess/code-runtime surfaces to the parent's
exact content (this branch claims none of them) and drop the net-zero
code-runtime-e2b/pty-e2b/lsp-e2b residue and its registrations
- widen serializeRemoteEnvironment to the seam's NodeJS.ProcessEnv
tombstone contract: an explicit undefined removes an ambient entry
- migrate the two E2B fixture Agent stubs to the Inbox-model interface
and Session.create
- re-apply the branch's gen-doc-graphs roles, THIRD_PARTY_NOTICES e2b
row, and packages/README group row (trimmed to the doc budget);
regenerate catalogs and re-record bilingual pairings
