Surface a node's explicit instance name in the `aura graph` viewer: a named leaf
renders its box head as `fast: SMA[length]` (the instance name as a `:`
declaration prefix), an unnamed leaf keeps the bare `SMA[length]`. The name
crosses two surfaces — a conditional `"name"` field in the JSON graph model
(engine half) and a `cellLabel` prefix in graph-viewer.js (viewer half).
Explicit-`.named()`-only; `node_name()`'s lowercased-type default is not
surfaced. `named()`'s non-empty rule is kept with its code unchanged, its doc
re-grounded to the load-bearing invariant (knob-address segment + Some/None
prefix switch).
Signed via the /boss auto-sign gate: all objective gates green (precondition,
self-review, grounding-check PASS) and a unanimous five-lens spec-skeptic panel
(criterion, grounding, scope-fork, ambiguity, plan-readiness). Two earlier blocks
were resolved before the unanimous round — a separator-ambiguity by an editorial
fix, and a scope-fork (which nodes carry the prefix) by an explicit user decision
recorded as a provenance-bearing reconciliation comment on the issue.
refs #58
