Add ranking_instructions to Search Mode

[CShorten]

Add ranking_instructions argument to Search Mode

What's changed

Adds a new optional ranking_instructions argument to the Query Agent's search-only mode, on both QueryAgent.search() and AsyncQueryAgent.search().

response = agent.search(
    "Find NDAs signed in 2024",
    collections=["FinancialContracts"],
    ranking_instructions="Prioritize recently signed documents over older ones.",
)

How it works

• The instructions are passed to the instruction-following reranker to guide relevance prioritization. They only affect the ordering of results, not which results are retrieved.
• The field is added to SearchModeRequestBase, so it applies to both the initial request (server-side query generation) and paginated requests via response.next(...) (direct search execution), and persists across pages — consistent with filtering and diversity_weight.
• Defaults to None and serializes as JSON null when not provided.

Tests

• Sync + async tests asserting that omitting the argument sends null in the request payload.
• Sync + async tests asserting that a provided string is sent verbatim and persists across pagination.

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	SAST	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca