graph: the rendering switch — chains view as the home (release polish 2)

The settings Graph section splits into two switches (owner, 2026-10-06):

- EXTRACTION (was the lone "Graph" row): the DATA channel — pipeline,
  auditor, prober graph tools. Key unchanged (graph.enabled), label now
  names its job; off = the graph stops growing, nothing is deleted.
- GRAPH RENDERING (new, graph.rendering, default on): display-only.
  Off = the home's main view is the CHAINS VIEW instead of the canvas;
  data, reasoning-chain model, and the pipeline keep working untouched.

The chains home (components/chains-home.tsx): ChainTableBody in flow —
same body as the overlay, same powers (query + sort, selection, the
delete fence with its confirm dialog), but onClose is absent so the
top-bar X does not render (the table IS the page; ChainTableBody now
takes onClose optionally). The chrome survivors float top-right below
the top bar: Import notes (ALWAYS — the entry-point law) + the cost
pill (GraphCostControl, now exported). The composer blob persists over
everything; the table scrolls CLEAR of it via a fixed pb-40 band (text
under a floating box is noise — unlike the canvas, which runs under).

Pick flow mirrors the overlay contract exactly (home lifts the pick
set; selectMode swaps the bar's confirm to Done). The chip relabels to
"Pick propositions" (no "from the map" — there is no map); while
picking, the chip row hides so the floating bar above the composer is
the one voice. Settings resolve rendering through the one core
resolver + renderingEnabled(); read server-side per navigation, so the
switch applies on the next visit home.

Smoke-verified live (headless browser): chains home renders without the
X, import + search + composer clearance confirmed, pick flow checked 2
propositions -> Done -> chip count -> practice session started with the
graph context carried (2 props, 2 chains), settings restored.

Known follow-ups (flagged, not built): after Done the bar morphs to the
table's Clear/Delete management bar while the chip also shows the count
(two voices, same set — the table's own editor law); /chat/new's pick
chip still says "from the map".

Tests: rendering in factory/sanitize/parse/resolve pins, the GraphSection
render pins (Extraction label + rendering row), the home-variant
chain-table pin (no close X). 1414 pass; tsc, lint, build green.

src/server/settings-body.ts

@@ -296,6 +296,10 @@ export function parseGraphSettingsBody(body: unknown): SettingsBodyResult<GraphS
 		if (typeof raw.enabled !== "boolean") return { ok: false, error: "enabled must be a boolean" };
 		settings.enabled = raw.enabled;
 	}
+	if (raw.rendering !== undefined) {
+		if (typeof raw.rendering !== "boolean") return { ok: false, error: "rendering must be a boolean" };
+		settings.rendering = raw.rendering;
+	}
 	if (raw.extractionChunkTokens !== undefined) {
 		if (typeof raw.extractionChunkTokens !== "number" || !Number.isFinite(raw.extractionChunkTokens)) {
 			return { ok: false, error: "extractionChunkTokens must be a number" };