* fix(sse): preserve parallel_tool_calls for GPT-5.6 ultra/max delegation under Codex Responses Lite (#7821)
* fix(codex): drop over-broad parallel_tool_calls allowlist entry — keep #2608 stripping intact (#7821)
The static RESPONSES_API_ALLOWLIST addition made parallel_tool_calls survive for
ALL models, breaking the #2608 non-passthrough stripping guarantee for gpt-5.5.
The real #7821 fix (isCodexDelegationDependentModel gating in
enforceCodexResponsesLiteParallelToolCalls) is model/effort-scoped and does not
need the allowlist entry — native Codex traffic returns before the allowlist runs.
