The function preview body — the one-line summary over a stacked argument list (each argument's
name above its own description, with type/repeatable icons, inactive ones dimmed RowZero-style). This
is the informative half, deliberately free of any collapse/close chrome so it can be reused verbatim
as a hover tooltip (compose it under a FunctionSignature); inside the editor it's the
collapsible body of FunctionPreviewPanel. Renders nothing when there's neither a summary nor
any arguments. Presentational — nothing here mutates the edit.
The function preview body — the one-line summary over a stacked argument list (each argument's name above its own description, with type/repeatable icons, inactive ones dimmed RowZero-style). This is the informative half, deliberately free of any collapse/close chrome so it can be reused verbatim as a hover tooltip (compose it under a FunctionSignature); inside the editor it's the collapsible body of FunctionPreviewPanel. Renders nothing when there's neither a summary nor any arguments. Presentational — nothing here mutates the edit.