Four tasks for cycle 0027 (spec docs/specs/0027-name-input-ports.md):
1. Add name: String to PortSpec (drop Copy) and thread all 16 construction
sites in one compile-gate task — aura-std nodes get real slot names, fixtures
get fixture names, derive_signature carries Role.name; port_json untouched so
the byte golden stays green and the full suite passes.
2. port_json appends the name; re-capture the model byte golden and update its
two substring twins (sink_has_empty_outs witnesses a leaf PortSpec.name in the
model, multi_input_composite witnesses a composite Role.name carried through).
3. Lock the per-node input-slot names (8 aura-std pins).
4. C8 realization note in the design ledger (cross-links C23).
refs #50
