Summary

ACP session persistence was dropping assistant reasoning metadata during save/restore.

This change forwards assistant reasoning, reasoning_details, and
codex_reasoning_items into SessionDB.append_message() so restored ACP
sessions retain the same assistant context they had before persistence.

Why this is a bug

hermes_state.SessionDB already supports storing and restoring these fields,
but acp_adapter.session.SessionManager._persist() only wrote the basic
message fields. As a result, ACP session restore silently degraded assistant
history by removing reasoning-related metadata.

That created an inconsistent round-trip:

• in-memory ACP history kept reasoning fields
• persisted ACP history lost them after restore

Changes

• update ACP session persistence to pass:
  • reasoning
  • reasoning_details
  • codex_reasoning_items
• add a regression test covering assistant reasoning round-trip persistence

Tests

Ran:

• uv run --with pytest --with pytest-xdist pytest tests/acp/test_session.py -q -n 4

Result:

• 31 passed