Cycle A of milestone 'The World — parameter-space & sweep'. A node declares
its tunable parameters in its C8 schema (ParamSpec { name, kind }, a third
NodeSchema field); Blueprint::param_space() aggregates them into one flat,
path-qualified param-space as a read-only projection of the graph-as-data.
Param identity is positional (slot after the deterministic inline order),
the name a non-load-bearing path-qualified debug symbol (C23). Vector knobs
(LinComb.weights) expand to N flat indexed entries; N is topology-fixed (C19).
compile/inline_composite are untouched — the compilat stays bit-identical.
Scope is declaration + aggregation + inspection only; binding (#31), sweep
enumeration (#32), search-range, constraint, and default-range are deferred.
refs #30
