Extends the conversation=<id> Portal tag (salvaged from PR #65183 by
@J-SUPHA) from main-loop-only to every LLM call in a conversation:
- agent/portal_tags.py: ContextVar-based conversation context.
nous_portal_tags() falls back to the ambient id when no explicit
session_id is passed, so every aux tag site (auxiliary_client,
chat_completion_helpers summary path, web_tools) inherits the tag
with zero per-call-site plumbing. Ambient id wins over explicit
per-segment ids since it carries the lineage root.
- hermes_state.py: SessionDB.get_conversation_root() — public wrapper
over the lineage walk; returns the ROOT session id, so one
user-facing conversation keeps a single conversation= value across
context-compression rotation, and delegate subagent trees tag as
their parent conversation.
- run_agent.py: run_conversation() publishes the root id for the turn
and resets it in finally. _conversation_root_id() resolves via
_parent_session_id for subagents.
- agent/moa_loop.py: MoA reference fan-out workers now run under
propagate_context_to_thread so advisor slots attribute to the acting
conversation (also fixes approval-callback propagation on that path).
- agent/title_generator.py: bare title thread republishes the context
from its session id (spawned after turn reset).
Tests: ContextVar semantics, cross-context isolation, thread-hop
propagation, lineage-root resolution incl. cycle guard.
