feat(ia): wave 1 — Import tab dissolves, Maintenance regroups by system, one extension home

Settings IA per the approved A3 design (the old layout was the two-app merge
fossilized):
- Import tab retired: ImportTriggerPanel + ImportTaskList deleted (manual
  /import scans stay API-level; imports arrive via downloads/extension, heal
  via the Layer-2 auto-refetch sweep, and show in Activity). ImportFiltersForm
  moves to Maintenance → 'Ingestion & filters' and loads its own settings; the
  import store shrinks to settings-only (no remaining consumers of the
  scan/task-list machinery). Overview's pending banner now points at Activity.
- Maintenance regrouped: Ingestion & filters / GPU agent & embeddings
  (GpuAgent, Failed processing, CPU embedding backfill) / Tagging (sliders,
  Heads, Aliases) / Library health (MissingFiles, Thumbnails, DB, Archive
  re-extract demoted last) / Storage.
- One extension home: BrowserExtensionCard moves from Settings → Overview to
  Subscriptions → Settings, above the API key bar it authenticates.
- Single-color import filter WIRED: skip_single_color/threshold existed since
  FC-2 but nothing read them (the audit module's docstring said as much) —
  now enforced on both import paths via the audit's canonical predicate
  (tolerance 30, matching the Cleanup card default; animated images exempt
  like the transparency check). Default stays off; test added.
- Dead weight: PlaceholderView (zero refs) and the permanently-disabled
  'Export failed logs (CSV — v2)' menu stub deleted; stale docs fixed
  (celery queue docstring, threshold comment citing retired tasks, ml
  package docstring, HeadsCard 'replaces Camie' blurb).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CDgx8bQS5YrGRK76v8HUnM

frontend/src/views/SettingsView.vue

@@ -17,7 +17,6 @@
     >
       <v-tab value="overview">Overview</v-tab>
       <v-tab value="activity">Activity</v-tab>
-      <v-tab value="import">Import</v-tab>
       <v-tab value="cleanup">Cleanup</v-tab>
       <v-tab value="maintenance">Maintenance</v-tab>
     </v-tabs>
@@ -34,31 +33,14 @@
           type="info" variant="tonal" class="mt-4" closable
         >
           {{ system.stats.tasks.pending + system.stats.tasks.queued }} import task(s) pending.
-          <v-btn variant="text" size="small" @click="tab = 'import'">Go to Import tab</v-btn>
+          <v-btn variant="text" size="small" @click="tab = 'activity'">View in Activity</v-btn>
         </v-alert>
-        <!-- Browser-extension install/download lives on Overview (moved
-             from Maintenance 2026-05-25). Overview is the discovery
-             surface for "things to set up"; Maintenance is for
-             housekeeping of already-set-up systems. -->
-        <BrowserExtensionCard class="mt-6" />
       </v-window-item>
 
       <v-window-item value="activity">
         <SystemActivityTab />
       </v-window-item>
 
-      <v-window-item value="import">
-        <!-- Order: filters → trigger → recent tasks. Filters hoisted above the
-             trigger (operator-flagged 2026-06-04); the task list stays
-             directly below the trigger so hit/miss feedback is adjacent to the
-             button that produced it (operator-flagged 2026-05-25). -->
-        <ImportFiltersForm />
-        <v-divider class="my-6" />
-        <ImportTriggerPanel />
-        <v-divider class="my-6" />
-        <ImportTaskList />
-      </v-window-item>
-
       <v-window-item value="cleanup">
         <CleanupView />
       </v-window-item>
@@ -73,21 +55,15 @@
 <script setup>
 import { onMounted, onUnmounted, ref, watch } from 'vue'
 import { useSystemStore } from '../stores/system.js'
-import { useImportStore } from '../stores/import.js'
 import SystemStatsCards from '../components/settings/SystemStatsCards.vue'
 import SystemActivitySummary from '../components/settings/SystemActivitySummary.vue'
 import SystemActivityTab from '../components/settings/SystemActivityTab.vue'
-import BrowserExtensionCard from '../components/settings/BrowserExtensionCard.vue'
-import ImportTriggerPanel from '../components/settings/ImportTriggerPanel.vue'
-import ImportFiltersForm from '../components/settings/ImportFiltersForm.vue'
-import ImportTaskList from '../components/settings/ImportTaskList.vue'
 import MaintenancePanel from '../components/settings/MaintenancePanel.vue'
 import CleanupView from './CleanupView.vue'
 import { useMLStore } from '../stores/ml.js'
 
 const tab = ref('overview')
 const system = useSystemStore()
-const importStore = useImportStore()
 const mlStore = useMLStore()
 
 let pollId = null
@@ -96,15 +72,7 @@ function startPolling() {
   if (pollId) return
   system.refreshStats()
   pollId = setInterval(() => {
-    if (!document.hidden) {
-      system.refreshStats()
-      if (tab.value === 'import') {
-        importStore.refreshStatus()
-        // Refresh the task list while a batch is in flight so the UI
-        // doesn't sit stale next to a ticking imported/skipped counter.
-        if (importStore.activeBatch) importStore.loadTasks(true)
-      }
-    }
+    if (!document.hidden) system.refreshStats()
   }, 5000)
 }
 
@@ -112,21 +80,11 @@ function stopPolling() {
   if (pollId) { clearInterval(pollId); pollId = null }
 }
 
-onMounted(() => {
-  startPolling()
-  importStore.loadSettings()
-  importStore.refreshStatus()
-  importStore.loadTasks(true)
-})
+onMounted(startPolling)
 onUnmounted(stopPolling)
 
 watch(tab, (t) => {
-  if (t === 'import') {
-    importStore.refreshStatus()
-    importStore.loadTasks(true)
-  } else if (t === 'maintenance') {
-    mlStore.loadSettings()
-  }
+  if (t === 'maintenance') mlStore.loadSettings()
 })
 </script>