Peek

Placeholder (to be expanded):

• Purpose: read values dynamically without knowing the concrete type.
• Core API: Peek, traversing fields/variants, reading scalars, sequences, maps.
• When to use: pretty-printers, diff tools, schema exporters.
• Safety: lifetime parameters tie to the backing value; no cloning unless supported by vtable.
• Examples: walk a struct, iterate a map, stringify with spans.