vision: wire radial-onion lens into shell.html (DEAD → WIRED)

[Zychs]

Vision

README feature title: Adaptive Scope-Aware Radial Branch Visualizer…
shell.html is the go-forward modular shell; radial is a first-class base lens per docs/ARCHITECTURE.md and docs/specs/radial-rerooting-spec.md.

Reality

• src/lenses/radial-onion.js is real layout math (~235–274 lines) but no shell imports it — ARCHITECTURE status: DEAD (reachable-as-code, unreachable-as-product).
• shell.html only mounts SpatialMapLens; UI copy says "Spatial-map lens only."
• Plan: docs/ghm2-development-plan.md Phase B.

Not this issue

Radial polish already tracked: #3 (dashed spokes), #4 (draw-cull), #7 (icons), #8 (tracking epic). This issue is wiring + lens picker, not layout polish.

Exit

• Lens picker (or equivalent) offers spatial | radial.
• Re-root path uses a decided accessible-branches semantic (see sibling issue).
• Status words flip: radial is WIRED in ARCHITECTURE/README; no more STUB/DEAD confusion.

Refs

docs/ghm2-development-plan.md Phase B · docs/ghm2-frontier-research-array.md lane 5 · docs/VERSIONING.md §5 status words