fix(02-08): cap content.browse-peer fan-out — root cause of Cloud first-visit hang

Instrumented the exact trigger the fresh-mount guard (previous commit)
didn't fully eliminate: on a fresh session, loadPeerFiles() fired one
content.browse-peer RPC per connected peer with zero concurrency cap
and a 30s per-call timeout. Confirmed on archi-dev-box: 13 of 14
concurrent browse-peer calls never settled at all (dead/unreachable
peers with no server-side timeout on that path) — that many
simultaneously open, indefinitely-pending same-origin requests starved
Chromium's connection pool, silently breaking every other same-origin
fetch for the rest of the session, including the lazy route chunk any
later folder/tab navigation needs. This — not the router or the click
handler — was the actual cause of "no folders open on click" after a
first Cloud visit.

Fix, mirroring PeerFiles.vue's existing PREVIEW_CONCURRENCY pattern for
the identical class of problem (content.preview-peer fan-out):
- Cap the browse-peer fan-out at 3 concurrent requests
  (BROWSE_PEER_CONCURRENCY, a queue+worker pool in loadPeerFiles()).
- Shorten each call's timeout from 30s to 10s (BROWSE_PEER_TIMEOUT_MS) —
  bounds how long any one dead peer can hold a connection.
- Wire an AbortController (aborted onUnmounted) through rpc-client's
  signal option for clean teardown.
- A timed-out/failed peer already resolved silently through
  resources.ts's own error-state path (no throw, no toast) — confirmed
  unchanged; the muted "N peers unreachable" line is the only surface.

No visual/behavioral change to the working case (D-01 rule) — peers
that answer still render exactly as before, just no longer share the
page with a dozen never-ending requests.

Full suite green (95 files / 774 tests), type-check and build clean,
keepAliveTabs.test.ts structural DOM assertions untouched.

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

neode-ui/src/views/Cloud.vue

@@ -402,7 +402,7 @@
 </template>
 
 <script setup lang="ts">
-import { computed, ref, watch, onActivated, onMounted } from 'vue'
+import { computed, ref, watch, onActivated, onMounted, onUnmounted } from 'vue'
 import { useRouter, RouterLink } from 'vue-router'
 import { useAppStore } from '../stores/app'
 import { useCloudStore } from '../stores/cloud'
@@ -769,20 +769,61 @@ interface PeerBrowse {
 
 const peerBrowseKey = (onion: string) => `cloud.peer-browse:${onion}`
 
+// 02-08 fix: content.browse-peer has no server-side timeout for an
+// unreachable/dead .onion peer — confirmed on real hardware that 13 of 14
+// concurrent calls to this method (one per connected peer, previously fired
+// with zero concurrency cap from loadPeerFiles below) never settled at all
+// within 15s+. That many simultaneously-open, indefinitely-pending same-
+// origin requests starved Chromium's connection pool and silently broke
+// every OTHER same-origin fetch for the rest of the session — including the
+// lazy route chunk any later tab/folder navigation needs (the actual cause
+// behind "no folders open on click" after a first Cloud visit). A single
+// dead peer's own RPC still costs at most this timeout once (maxRetries: 1
+// already prevented the ×3 retry-storm version of this bug); the fix here
+// is bounding how many of these can be simultaneously in flight and how
+// long any one of them is allowed to hold a connection open, mirroring the
+// PREVIEW_CONCURRENCY pattern PeerFiles.vue already uses for the identical
+// class of problem (content.preview-peer fan-out).
+const BROWSE_PEER_TIMEOUT_MS = 10_000
+const browsePeerAborter = new AbortController()
+onUnmounted(() => browsePeerAborter.abort())
+
 function browsePeer(peer: PeerNode): Promise<void> {
   return resources.refresh<PeerBrowse>(peerBrowseKey(peer.onion), async () => {
     const t0 = Date.now()
     const res = await rpcClient.call<{ items?: CatalogItem[]; transport?: string }>({
       method: 'content.browse-peer',
       params: { onion: peer.onion },
-      timeout: 30000,
+      timeout: BROWSE_PEER_TIMEOUT_MS,
       // One slow/unreachable peer must cost its timeout ONCE, not ×3 —
       // the retry loop is why one dead peer meant a 90s spinner.
       maxRetries: 1,
       dedup: true,
+      signal: browsePeerAborter.signal,
     })
     return { items: res?.items ?? [], transport: res?.transport ?? null, latencyMs: Date.now() - t0 }
   })
+  // A timed-out/failed peer resolves through resources.ts's own catch path
+  // (loadState -> 'error', no throw here) — it never blocks or delays any
+  // other peer's slot, and the UI already surfaces this silently (the
+  // muted "N peers unreachable — showing what answered" line below, no
+  // toast) rather than as an error the user must dismiss.
+}
+
+/** Concurrency-capped content.browse-peer fan-out — bounds how many of
+ * these can be simultaneously in flight (see BROWSE_PEER_TIMEOUT_MS note
+ * above). Matches PeerFiles.vue's PREVIEW_CONCURRENCY convention. */
+const BROWSE_PEER_CONCURRENCY = 3
+async function runBrowsePeerPool(targets: PeerNode[]): Promise<void> {
+  let cursor = 0
+  async function worker(): Promise<void> {
+    while (cursor < targets.length) {
+      const peer = targets[cursor++]!
+      await browsePeer(peer).catch(() => {}) // errors already land in the resource's own error state
+    }
+  }
+  const workerCount = Math.min(BROWSE_PEER_CONCURRENCY, targets.length)
+  await Promise.all(Array.from({ length: workerCount }, () => worker()))
 }
 
 function peerBrowseEntry(onion: string) {
@@ -835,7 +876,9 @@ const peerFilesLoading = computed(() =>
   peerNodes.value.length > 0 && peerFiles.value.length === 0 && peerFilesPending.value > 0 && peerFilesErrors.value < peerNodes.value.length,
 )
 
-/** Fan out content.browse-peer; each peer renders as it resolves. */
+/** Fan out content.browse-peer, capped at BROWSE_PEER_CONCURRENCY at a time;
+ * each peer renders as it resolves regardless of the cap (the aggregation
+ * above is reactive per-entry, not gated on the whole batch finishing). */
 async function loadPeerFiles(force = false) {
   if (peerNodes.value.length === 0) await loadPeers()
   const targets = peerNodes.value.filter(p => {
@@ -844,8 +887,7 @@ async function loadPeerFiles(force = false) {
     const stale = e.fetchedAt === null || Date.now() - e.fetchedAt > 30_000
     return e.loadState === 'idle' || e.loadState === 'error' ? true : stale
   })
-  // Fire-and-collect: the computed aggregation updates per resolution.
-  await Promise.allSettled(targets.map(p => browsePeer(p)))
+  await runBrowsePeerPool(targets)
 }
 
 const filteredPeerFiles = computed(() =>