Issue #3584010: Add FilterableRagTool with per-index derivatives and attribute filtering
Adds a new deriver-based FunctionCall plugin that produces one derivative per ai_search.index.* config. Each derivative is scoped to a single Search API index and exposes attribute fields as optional context_definitions, allowing LLMs to pass filter values as query conditions. The existing RagTool remains untouched for backwards compatibility.
Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com
Closes #3584010