admin: overview redesign, device scope, one formatting contract (milestone 39)

The Overview page takes the decided visual language (specs/ui-visual-redesign.md): four centred totals with their Activity links, a smoothed area chart of total and blocked queries with point hover and a tooltip beside the point, a stacked client chart in eight distinct hues plus one Other band, and a card row with the cache hit rate, the query types as a single-hue ramp ring, and the upstream breakdown.

GET /api/overview takes a client parameter; the scoped read uses idx_query_log_ts and the cache keeps scoped slots. The device selector beside the period selector is URL state, so a scoped view is a link, and the tile links carry the scope into Activity.

All numbers go through admin/src/lib/format.ts: grouped counts, two-decimal percentages, one-decimal rates, durations as the two largest nonzero units. A sweep test refuses toFixed, toLocaleString, Intl.NumberFormat and padStart anywhere else.

Chrome: one 4px radius from the metrics constants, shared Card with a prominent title and description, the sidebar grouped into Monitoring and System with a status block (protection, queries per minute on Overview, uptime), and the accent darkened to 5.43:1 on its wash.

Not built: the spec's ranked-list primitive, which has no consumer and no API rows. Codex could not review sessions B to D, its endpoint returned 404 for every call on 2026-09-03; the owner accepted the smoke-server screenshots.

admin/src/ui/ConfirmDialog.tsx

@@ -11,7 +11,7 @@
 import type { ReactNode } from "react";
 import * as stylex from "@stylexjs/stylex";
 import { Dialog as AriaDialog, Heading, Modal, ModalOverlay } from "react-aria-components";
-import { colors, layers } from "./tokens.stylex";
+import { colors, layers, metrics } from "./tokens.stylex";
 import { styles as shared } from "./styles";
 
 interface Props {
@@ -77,7 +77,7 @@ const styles = stylex.create({
 	},
 	dangerButton: {
 		cursor: { default: "pointer", ":disabled": "not-allowed" },
-		borderRadius: "0.25rem",
+		borderRadius: metrics.radius,
 		borderStyle: "none",
 		backgroundColor: colors.danger,
 		color: colors.primaryText,