fix(rebase): migrate the replayed E2B branch onto the rebased parent

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

packages/README.md

@@ -6,7 +6,7 @@ Packages use the `@deepseek-ai/dsh-*` scope. Cordis `Service` subclasses and fun
 
 ## Hierarchy
 
-Groups contain packages at `packages/<group>/<pkg>/`; names remain `@deepseek-ai/dsh-<pkg>`. **Group READMEs own package/ctx-key maps.**
+Groups hold `packages/<group>/<pkg>/`; names stay `@deepseek-ai/dsh-<pkg>`. **Group READMEs own package/ctx-key maps.**
 
 | Group | Role | Release expectation |
 |---|---|---|