feat(02-02): tracer tab refreshes silently and every side effect is placed

Puts Marketplace.vue's data on the cache and adds the subtle background-
refresh indicator D-05 calls for:

- RefreshIndicator.vue: presentational, state-driven (ResourceLoadState).
  Renders nothing for ready/idle/loading — a first load is the view's own
  skeleton's job, not this component's — and a role="status"
  aria-live="polite" spinner only while refreshing. A fixed-size outer slot
  keeps its appearance/disappearance from ever shifting layout.
- Marketplace.vue: loadCommunityMarketplace()/loadBitcoinPruneStatus() move
  onto useCachedResource behind shared keys app-catalog (300s TTL, persist —
  near-static catalog, D-06 discretion) and bitcoin.prune-status (default
  30s TTL, persist — both non-sensitive/small per T-02-01). app-catalog is a
  shared key so Discover.vue's identical loader picks up the same entry
  without its own conversion in 02-04. Error handling is keep-last-value
  (D-07): a rejected refresh sets the existing communityError banner ref,
  never a toast, and prior app cards stay on screen.
- Side-effect audit (the precedent 02-04 repeats across remaining tabs):
  marketplaceAnimationDone is genuinely once-per-session intro state, stays
  in onMounted; the two data loads needed no onMounted/onActivated hook of
  their own at all — useCachedResource's internal onActivated (wired in
  Task 1) already revalidates them on every kept-alive tab re-entry,
  staleness-gated so a quick revisit issues no fetch. No interval,
  subscription or window listener exists in this view, so no onDeactivated
  teardown was needed either.
- Tests: RefreshIndicator's full render-nothing/render-something matrix
  added to keepAliveTabs.test.ts (no router dependency, safe to colocate).
  The D-07 rejected-refresh-keeps-content-and-no-toast test mounts
  Marketplace.vue itself but lives in a new file,
  views/__tests__/MarketplaceRefresh.test.ts, following the in-repo
  CloudPeersRefresh.test.ts mount-the-view pattern — vi.mock('vue-router')
  is hoisted file-wide, so colocating it in keepAliveTabs.test.ts would
  clobber that file's real createRouter/createMemoryHistory used by the
  DashboardRouterView tests (Rule 3 auto-fix; deviation from the plan's
  literal single-test-file file list, documented here for the SUMMARY).
  Marketplace.vue gains a defineExpose({ loadCommunityMarketplace,
  loadBitcoinPruneStatus }) for tests, mirroring Cloud.vue's existing
  defineExpose({ loadPeers }).

Full suite (87 files / 709 tests), type-check and build all green; the
built Marketplace chunk carries refresh-indicator.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

neode-ui/src/components/RefreshIndicator.vue

@@ -0,0 +1,60 @@
+<template>
+  <div class="refresh-indicator-slot" aria-hidden="false">
+    <div
+      v-if="state === 'refreshing'"
+      class="refresh-indicator"
+      role="status"
+      aria-live="polite"
+    >
+      <span class="refresh-indicator-spinner" aria-hidden="true" />
+      <span class="sr-only">{{ label ?? 'Refreshing…' }}</span>
+    </div>
+  </div>
+</template>
+
+<script setup lang="ts">
+import type { ResourceLoadState } from '@/stores/resources'
+
+// Subtle background-refresh indicator (D-05): visible only while a cached
+// resource is revalidating behind already-rendered content. A first load
+// is the view's own skeleton's job, not this component's — 'loading'
+// intentionally renders nothing here, same as 'ready'/'idle'. No stale-age
+// text or "last updated" badge (D-05 rules those out).
+defineProps<{
+  state: ResourceLoadState
+  label?: string
+}>()
+</script>
+
+<style scoped>
+/* Fixed-size outer slot so the indicator appearing/disappearing never
+   shifts surrounding layout — callers can drop this inline without also
+   reserving space themselves. */
+.refresh-indicator-slot {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  width: 1rem;
+  height: 1rem;
+  flex-shrink: 0;
+}
+
+.refresh-indicator {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+}
+
+.refresh-indicator-spinner {
+  width: 0.875rem;
+  height: 0.875rem;
+  border: 2px solid rgba(255, 255, 255, 0.15);
+  border-top-color: rgba(255, 255, 255, 0.55);
+  border-radius: 50%;
+  animation: refresh-indicator-spin 0.8s linear infinite;
+}
+
+@keyframes refresh-indicator-spin {
+  to { transform: rotate(360deg); }
+}
+</style>