follows renders as the double-shaft glyph (⟹), supports stays single

Per docs/vision-edge-glyph.md: a `follows` edge (the derivation backbone)
draws two parallel shaft tails offset along the edge normal by a fixed
SCREEN-space gap (FOLLOWS_GAP_RATIO x edgeWidth — constant on screen at
every zoom, like the stroke width), converging on the shared single
arrowhead; `supports` keeps the plain single line (dashed was rejected
earlier — not revisited).

- CanvasEdge carries the edge type; graph-view passes it from the snapshot.
- followsEdgeGeometry (pure, tested): offset tails + convergence at the
  head base — a strictly-parallel pair would poke out beside the head
  whenever the screen-fixed gap exceeds the head's world-scaled base
  half-width. The offset tails sit farther from the source center than
  the axis start, so the source disc never clips them.
- Edge paths leave buildGeometry: their gap is anchored to the CURRENT
  camera scale, so buildEdgePaths(k) rebuilds on geoVersion changes and
  camera-scale drift (> EDGE_PATHS_ZOOM_EPSILON) — 0.08ms per rebuild at
  211 edges; pans and settle frames reuse the cached paths.
- Legend entry bottom-right: ⟹ follows · → supports.

Live-verified: isolated follows edge (search "likelihood") shows two 1px
shafts with a ~3px centerline gap converging into one 8px-base shared
head; gap measured constant on screen at 0.2x, 1x, and 5x fit zoom while
heads/nodes scale. Gates: tsc, 435/435 tests, lint, build.

components/graph-view.tsx

@@ -753,7 +753,7 @@ export function GraphView() {
 				y: positions.get(n.id)?.y ?? 0,
 				label: n.name,
 			})),
-			edges: snapshot.edges.map((e) => ({ from: e.from, to: e.to })),
+			edges: snapshot.edges.map((e) => ({ from: e.from, to: e.to, type: e.type })),
 			clusters: snapshot.clusters.map((c) => ({ id: c.id, label: c.label, members: c.members })),
 			colors: {
 				node: tokenHex(NODE_COLOR_TOKEN),
@@ -896,6 +896,19 @@ export function GraphView() {
 				</div>
 			)}
 
+			{/* Edge glyph legend (bottom-right; the pipeline status pills own
+			    the bottom-left). ⟹ follows (the derivation backbone) · →
+			    supports — DECIDED 2026-09-14, docs/vision-edge-glyph.md. */}
+			{!isEmpty && (
+				<div className="pointer-events-none absolute bottom-3 right-3 z-10 flex items-center gap-2 rounded-full border bg-card/85 px-3 py-1.5 text-xs text-muted-foreground shadow-lg backdrop-blur">
+				<span className="font-medium text-foreground">⟹</span>
+				<span>follows</span>
+				<span className="text-muted-foreground/60">·</span>
+				<span className="font-medium text-foreground">→</span>
+				<span>supports</span>
+			</div>
+			)}
+
 			{/* Background pipeline status: what is currently running. */}
 			{pipelineRuns.length > 0 && (
 				<div className="absolute bottom-3 left-3 z-10 flex flex-col gap-1.5">