swarm-ui: delete StatusChip, migrate its 3 callers to shared Badge

mara: non-interactive Badge and StatusChip render identically (same
padding/radius/font, same tone-to-color mapping) and StatusChip's
4-tone/single-label shape is a strict subset of Badge's — no real
reason to keep both. Deletes StatusChip.tsx/.css, migrates AgentsPage's
config-PR chip, HivesPage's freshness chip, and ComponentsPage's own
table-status sample to Badge (tone/value, no onClick). Also drops the
now-redundant standalone StatusChip demo section on /components (the
Badge section already covers all 4 former chip tones plus accent).

Updated the two stale StatusChip references outside swarm-ui too:
design-guide.md's component-list example and colors.css's WCAG-
contrast-rationale comment.

frontend/packages/swarm-ui/src/pages/AgentsPage.tsx

@@ -21,6 +21,7 @@
 import { useState } from 'preact/hooks';
 import { ApiErrorPanel } from '@hive/shared/api-error-panel.js';
 import { readApiError, type ProblemDetails } from '@hive/shared/api-error.js';
+import { Badge } from '@hive/shared/badge.js';
 import { Button } from '../ui/button/Button.js';
 import { Dialog } from '../ui/dialog/Dialog.js';
 import { Panel } from '../ui/panel/Panel.js';
@@ -29,7 +30,6 @@ import {
   useRefreshInterval,
   type RefreshIntervalMs,
 } from '../ui/refresh-interval/RefreshInterval.js';
-import { StatusChip } from '../ui/status-chip/StatusChip.js';
 import { Table, type TableColumn } from '../ui/table/Table.js';
 import { CreateAgentForm } from './CreateAgentForm.js';
 
@@ -50,9 +50,9 @@ const COLUMNS: TableColumn<AgentRow>[] = [
     header: 'config PR',
     render: (a) =>
       a.configPr ? (
-        <StatusChip
+        <Badge
           tone="warning"
-          label={
+          value={
             a.configPr.html_url ? (
               <a href={a.configPr.html_url} target="_blank" rel="noreferrer">
                 #{a.configPr.pr_number}