Deduplicates the sidecar handling across 9 sites:
- substitute_api_content(): 2 API-bound pop+substitute sites
(chat_completion_helpers, transport — conversation_loop keeps its
inline pop because the current-turn compose fallback needs the value)
- drop_stale_api_content(): 4 rewrite-drop sites
(context_compressor x2, replay_cleanup, agent_runtime_helpers)
- extract_api_content_sidecar(): 3 gateway forwarding sites
(gateway/session, gateway/slash_commands, cli_commands_mixin)
Also: restore the eager _pending_cli_user_message clear on the early
row-creation try (was lost when the crash-persist moved after prefetch —
a crash in compression between the two tries would leave a stale staged
input), and fix a comment indentation nit in run_agent.py.
Co-authored-by: Soju06 <qlskssk@gmail.com>
kshitijk4poor
39efad89a8