Resolve target fields to registry-backed binding plans with evidence

Answers "which registry fields supply these target fields, and on what evidence" by climbing a cost ladder — memo, name retrieval, corpus mining, then optional LLM synthesis — and stopping at the first rung that meets min_trust. Read-mostly, on the read scope: plans proposed above the memo are written back as inert candidate rows so a tenant pays for a rung at most once, and nothing here activates, retires or verifies a plan. A target nothing could bind comes back with an empty bindings array — an abstention, never an omission.