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/lsp/lsp-local/tests/instance.spec.ts

@@ -56,7 +56,6 @@ function makeInstance(
     maxStderrBytes: 100_000,
     shutdownTimeoutMs: 200,
     killGraceMs: 200,
-    pathToFileUri: path => pathToFileURL(path).href,
     ...overrides,
   }, spawnSubprocess, writer)
   live.push(instance)
@@ -92,7 +91,6 @@ function scriptInstance(script: string, overrides: Partial<InstanceSpec> = {}):
     maxStderrBytes: 100_000,
     shutdownTimeoutMs: 150,
     killGraceMs: 150,
-    pathToFileUri: path => pathToFileURL(path).href,
     ...overrides,
   }, spawnSubprocess)
   live.push(instance)