Resolve a nodeId.param input key against the document + registry — the
ONE lookup every caller uses to decide whether a key is a declared
parameter. Returns undefined for a malformed key (no dot), a key naming
no node, or a node with no such param — regardless of whether the key
also appears in doc.inputs (a node can accept a param override the
Player form never exposed).
Resolve a
nodeId.paraminput key against the document + registry — the ONE lookup every caller uses to decide whether a key is a declared parameter. Returns undefined for a malformed key (no dot), a key naming no node, or a node with no such param — regardless of whether the key also appears indoc.inputs(a node can accept a param override the Player form never exposed).