fix(02-11): gate three leaked background pollers to activate/deactivate

Fleet.vue's useFleetData() (60s telemetry.fleet-status/-alerts poll),
Server.vue's FipsNetworkCard.vue (15s fips.status poll), and Web5.vue's
Web5Monitoring.vue (30s system.stats poll — redundant with Home.vue's
own correctly-gated 10s poll of the same store) all armed their
setInterval in onMounted and only disarmed it in onUnmounted/
onBeforeUnmount. That was harmless before 02-04 registered their
owning views in KEEP_ALIVE_PATHS (the view was destroyed on every
tab-away, so the teardown hook fired every time); once KeepAlive keeps
the instance alive, the teardown hook never fires again and the poll
ran forever in the background regardless of which dashboard tab was
showing.

Gated arm/disarm to onActivated/onDeactivated, mirroring Server.vue's
own vpnPollInterval fix from 02-04 exactly. Added regression tests to
keepAliveLifecycle.test.ts mounting each real component under a
synthetic KeepAlive with fake timers; confirmed RED against the
pre-fix code (git stash) before confirming GREEN with the fix restored.

Full suite (95 files/788 tests), type-check and build all green.
keepAliveTabs.test.ts is byte-for-byte unmodified.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

neode-ui/src/views/fleet/useFleetData.ts

@@ -1,6 +1,6 @@
 /** Composable encapsulating fleet telemetry data fetching, types, and utilities */
 
-import { ref, computed, onMounted, onUnmounted, watch } from 'vue'
+import { ref, computed, onMounted, onUnmounted, onActivated, onDeactivated, watch } from 'vue'
 import { rpcClient } from '@/api/rpc-client'
 import type { ChartDataset } from '@/components/LineChart.vue'
 
@@ -480,17 +480,44 @@ export function useFleetData() {
 
   // --- Lifecycle ---
 
+  // 02-11 gap closure: `startAutoRefresh()`'s 60s poll used to be armed only
+  // in onMounted and disarmed only in onUnmounted — harmless before Fleet
+  // joined KEEP_ALIVE_PATHS (02-04), since leaving the tab fully unmounted
+  // this composable's owning component and onUnmounted fired every time.
+  // Once Fleet is KeepAlive'd, onUnmounted never fires again after the first
+  // visit, so the poll ran forever in the background regardless of tab
+  // visibility — the exact off-screen-drain class 02-04's own audit
+  // convention exists to prevent, missed here because that audit grepped
+  // Fleet.vue itself (which has no lifecycle side effects of its own) and
+  // never extended to this composable it delegates to. Arm/disarm now
+  // follows activate/deactivate, mirroring Server.vue's vpnPollInterval
+  // fix from 02-04; `startAutoRefresh()` already clears any existing timer
+  // first, so calling it from both onMounted and onActivated on a fresh
+  // KeepAlive-wrapped mount is safe and idempotent.
+  function armFleetPoll() {
+    if (autoRefresh.value) startAutoRefresh()
+  }
+  function disarmFleetPoll() {
+    stopAutoRefresh()
+  }
+
   onMounted(async () => {
     updateChartWidth()
     window.addEventListener('resize', updateChartWidth)
     await refreshAll()
-    if (autoRefresh.value) {
-      startAutoRefresh()
-    }
+    armFleetPoll()
+  })
+
+  onActivated(() => {
+    armFleetPoll()
+  })
+
+  onDeactivated(() => {
+    disarmFleetPoll()
   })
 
   onUnmounted(() => {
-    stopAutoRefresh()
+    disarmFleetPoll()
     window.removeEventListener('resize', updateChartWidth)
   })