Companion PR to #27590. Sweeps remaining stale references to the
LLM-summary path that landed in main with #27590 but weren't fully
caught in the followup cleanup commit.
Real rewrites:
- user-guide/sessions.md: 'Session Search Tool' section rewritten to
describe the three calling shapes (discovery / scroll / browse) with
worked examples. Adds the 'Optional parameters' subsection covering
sort and role_filter.
- user-guide/features/memory.md: 'Session Search' overview rewritten,
comparison table updated (speed: ms instead of LLM summarization,
added explicit free-cost row, link to sessions.md for details).
Stale-claim sweeps:
- user-guide/configuring-models.md: drop the 'Session Search' row from
the aux-model override table (no aux model anymore), drop session
search from the auxiliary-models list.
- user-guide/features/codex-app-server-runtime.md: drop session_search
from the ChatGPT-subscription cost note, drop the session_search
block from the per-task override config example.
- developer-guide/provider-runtime.md: drop 'session search
summarization' from the auxiliary tasks list.
- developer-guide/agent-loop.md: drop session search from the
auxiliary fallback chain list.
- user-guide/skills/.../autonomous-ai-agents-hermes-agent.md: drop
session_search from the 'auxiliary models not working' debug step.
Untouched (still accurate as tool-name mentions, not behavioral claims):
- features/tools.md, features/honcho.md, features/acp.md
- cli.md, sessions.md (other sections)
- developer-guide/tools-runtime.md, agent-loop.md (line 157)
- acp-internals.md, adding-tools.md, prompt-assembly.md
- reference/toolsets-reference.md, reference/tools-reference.md