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

scripts/gen-doc-graphs.ts

@@ -70,6 +70,7 @@ const GROUP_ORDER = [
   'bash',
   'pty',
   'sandbox',
+  'e2b',
   'fs',
   'skill',
   'compact',
@@ -321,12 +322,20 @@ const SERVICE_ROLES: ServiceRole[] = [
     mode: 'core',
     note: 'Folds revisioned objective state from the session log and keeps live continuation activation process-local.',
   },
+  {
+    key: 'e2b',
+    pkg: 'e2b',
+    title: 'E2B sandbox lifecycle owner',
+    mode: 'core',
+    consumers: ['fs-e2b', 'subprocess-e2b'],
+    note: 'Owns one shared E2B SDK handle, remote working directory, and final sandbox disposition so both fundamental E2B providers inhabit the same Linux runtime.',
+  },
   {
     key: 'subprocess',
     pkg: 'subprocess',
     title: 'Subprocess seam',
     mode: 'seam',
-    implementations: ['subprocess-local'],
+    implementations: ['subprocess-local', 'subprocess-e2b'],
     consumers: ['bash-local', 'bash-sandbox', 'pty-local', 'lsp-local', 'subagent-acp', 'subagent-codex', 'subagent-claude-code'],
     note: 'The bash executors, the PTY shell backend, the LSP host, and the out-of-process ACP, Codex, and Claude Code subagent backends spawn through ctx.subprocess; the service owns process coordinates, tree/session lifetime, stdio dispositions, terminal mechanics, and kill escalation.',
   },
@@ -405,7 +414,7 @@ const SERVICE_ROLES: ServiceRole[] = [
     pkg: 'fs',
     title: 'Filesystem provider seam',
     mode: 'seam',
-    implementations: ['fs-local', 'fs-sandbox'],
+    implementations: ['fs-local', 'fs-sandbox', 'fs-e2b'],
     consumers: ['tool-fs'],
     companions: ['fs-policy'],
     note: 'tool-fs executes read/write/edit through ctx.fs; fs-sandbox fences mutations by the shared sandbox mode; fs-policy contributes observed-state checks through the fs/* event gate.',