feat(fc2b): Settings Maintenance tab

MaintenancePanel hosts: backfill + centroid recompute trigger cards,
the five suggestion-threshold sliders (autosave on slider release),
the allowlist table (inline editable min_confidence, delete), and the
alias table (mapping display, delete). Wired as a third Settings tab,
ML settings loaded lazily when the tab opens.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/settings/AliasTable.vue

@@ -0,0 +1,43 @@
+<template>
+  <v-card>
+    <v-card-title>Tag aliases ({{ store.rows.length }})</v-card-title>
+    <v-data-table-virtual
+      :headers="headers" :items="store.rows" :loading="store.loading"
+      height="360" density="compact"
+      no-data-text="No aliases yet — create one from a suggestion's ⋮ menu."
+    >
+      <template #item.mapping="{ item }">
+        <code>{{ item.alias_string }}</code>
+        <span class="mx-2">→</span>
+        <strong>{{ item.canonical_tag_name }}</strong>
+      </template>
+      <template #item.actions="{ item }">
+        <v-btn
+          icon="mdi-delete" size="x-small" variant="text" color="error"
+          @click="store.remove(item.alias_string, item.alias_category)"
+        />
+      </template>
+    </v-data-table-virtual>
+  </v-card>
+</template>
+
+<script setup>
+import { onMounted } from 'vue'
+import { useAliasesStore } from '../../stores/aliases.js'
+
+const store = useAliasesStore()
+const headers = [
+  { title: 'Mapping', key: 'mapping', sortable: false },
+  { title: 'Category', key: 'alias_category', sortable: true, width: 130 },
+  { title: '', key: 'actions', sortable: false, width: 60 }
+]
+onMounted(() => store.load())
+</script>
+
+<style scoped>
+code {
+  background: rgb(var(--v-theme-surface-light));
+  padding: 1px 6px; border-radius: 4px;
+  font-family: 'JetBrains Mono', monospace;
+}
+</style>

frontend/src/components/settings/AllowlistTable.vue

@@ -0,0 +1,48 @@
+<template>
+  <v-card>
+    <v-card-title>Allowlisted tags ({{ store.rows.length }})</v-card-title>
+    <v-data-table-virtual
+      :headers="headers" :items="store.rows" :loading="store.loading"
+      height="360" density="compact"
+      no-data-text="No tags on the allowlist yet — accept a suggestion to add one."
+    >
+      <template #item.min_confidence="{ item }">
+        <v-text-field
+          :model-value="item.min_confidence" type="number"
+          density="compact" hide-details style="max-width: 100px;"
+          min="0.05" max="1" step="0.05"
+          @update:model-value="(v) => onThreshold(item.tag_id, v)"
+        />
+      </template>
+      <template #item.actions="{ item }">
+        <v-btn
+          icon="mdi-delete" size="x-small" variant="text" color="error"
+          @click="store.remove(item.tag_id)"
+        />
+      </template>
+    </v-data-table-virtual>
+  </v-card>
+</template>
+
+<script setup>
+import { onMounted } from 'vue'
+import { useAllowlistStore } from '../../stores/allowlist.js'
+
+const store = useAllowlistStore()
+const headers = [
+  { title: 'Tag', key: 'tag_name', sortable: true },
+  { title: 'Kind', key: 'tag_kind', sortable: true, width: 110 },
+  { title: 'Min confidence', key: 'min_confidence', sortable: false, width: 140 },
+  { title: '', key: 'actions', sortable: false, width: 60 }
+]
+onMounted(() => store.load())
+
+let debounce = null
+function onThreshold(tagId, value) {
+  if (debounce) clearTimeout(debounce)
+  debounce = setTimeout(() => {
+    const v = parseFloat(value)
+    if (v > 0 && v <= 1) store.updateThreshold(tagId, v)
+  }, 500)
+}
+</script>

frontend/src/components/settings/CentroidRecomputeCard.vue

@@ -0,0 +1,30 @@
+<template>
+  <v-card>
+    <v-card-title>Tag centroids</v-card-title>
+    <v-card-text>
+      <p class="text-body-2 mb-3">
+        Rebuild the per-tag SigLIP centroids that power similarity-based
+        suggestions. Runs nightly automatically; trigger manually after a
+        large tagging session.
+      </p>
+      <v-btn color="primary" rounded="pill" :loading="busy" @click="run">
+        <v-icon start>mdi-vector-triangle</v-icon> Recompute centroids
+      </v-btn>
+      <span v-if="done" class="ml-3 text-caption">Enqueued.</span>
+    </v-card-text>
+  </v-card>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+import { useMLStore } from '../../stores/ml.js'
+const store = useMLStore()
+const busy = ref(false)
+const done = ref(false)
+async function run() {
+  busy.value = true
+  try { await store.triggerRecomputeCentroids(); done.value = true }
+  catch (e) { window.__fcToast?.({ text: e.message, type: 'error' }) }
+  finally { busy.value = false }
+}
+</script>

frontend/src/components/settings/MLBackfillCard.vue

@@ -0,0 +1,29 @@
+<template>
+  <v-card>
+    <v-card-title>ML backfill</v-card-title>
+    <v-card-text>
+      <p class="text-body-2 mb-3">
+        Re-run Camie + SigLIP on images missing predictions or embeddings
+        for the current model versions. Safe to re-run.
+      </p>
+      <v-btn color="primary" rounded="pill" :loading="busy" @click="run">
+        <v-icon start>mdi-refresh</v-icon> Run backfill now
+      </v-btn>
+      <span v-if="done" class="ml-3 text-caption">Enqueued.</span>
+    </v-card-text>
+  </v-card>
+</template>
+
+<script setup>
+import { ref } from 'vue'
+import { useMLStore } from '../../stores/ml.js'
+const store = useMLStore()
+const busy = ref(false)
+const done = ref(false)
+async function run() {
+  busy.value = true
+  try { await store.triggerBackfill(); done.value = true }
+  catch (e) { window.__fcToast?.({ text: e.message, type: 'error' }) }
+  finally { busy.value = false }
+}
+</script>

frontend/src/components/settings/MLThresholdSliders.vue

@@ -0,0 +1,40 @@
+<template>
+  <v-card>
+    <v-card-title>Suggestion thresholds</v-card-title>
+    <v-card-text v-if="store.settings">
+      <v-row v-for="f in fields" :key="f.key">
+        <v-col cols="12">
+          <v-slider
+            v-model="local[f.key]" :label="f.label"
+            min="0" max="1" step="0.05" thumb-label hide-details
+            color="accent" @end="save"
+          />
+        </v-col>
+      </v-row>
+    </v-card-text>
+    <v-card-text v-else><v-skeleton-loader type="paragraph" /></v-card-text>
+  </v-card>
+</template>
+
+<script setup>
+import { reactive, watch } from 'vue'
+import { useMLStore } from '../../stores/ml.js'
+
+const store = useMLStore()
+const fields = [
+  { key: 'suggestion_threshold_artist', label: 'Artist' },
+  { key: 'suggestion_threshold_character', label: 'Character' },
+  { key: 'suggestion_threshold_copyright', label: 'Copyright' },
+  { key: 'suggestion_threshold_general', label: 'General' },
+  { key: 'centroid_similarity_threshold', label: 'Centroid similarity' }
+]
+const local = reactive({})
+watch(() => store.settings, (s) => { if (s) Object.assign(local, s) }, { immediate: true })
+
+async function save() {
+  const patch = {}
+  for (const f of fields) patch[f.key] = local[f.key]
+  try { await store.patchSettings(patch) }
+  catch (e) { window.__fcToast?.({ text: e.message, type: 'error' }) }
+}
+</script>

frontend/src/components/settings/MaintenancePanel.vue

@@ -0,0 +1,32 @@
+<template>
+  <div class="fc-maint">
+    <p class="text-body-2 mb-4">
+      Machine-assisted tagging controls. Backfill and centroid recompute run
+      nightly automatically; the allowlist auto-applies accepted tags to new
+      and existing images.
+    </p>
+    <div class="fc-maint__grid">
+      <MLBackfillCard />
+      <CentroidRecomputeCard />
+    </div>
+    <MLThresholdSliders class="mt-4" />
+    <AllowlistTable class="mt-4" />
+    <AliasTable class="mt-4" />
+  </div>
+</template>
+
+<script setup>
+import MLBackfillCard from './MLBackfillCard.vue'
+import CentroidRecomputeCard from './CentroidRecomputeCard.vue'
+import MLThresholdSliders from './MLThresholdSliders.vue'
+import AllowlistTable from './AllowlistTable.vue'
+import AliasTable from './AliasTable.vue'
+</script>
+
+<style scoped>
+.fc-maint__grid {
+  display: grid;
+  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
+  gap: 16px;
+}
+</style>

frontend/src/views/SettingsView.vue

@@ -5,6 +5,7 @@
     <v-tabs v-model="tab" color="accent" class="mb-4">
       <v-tab value="overview">Overview</v-tab>
       <v-tab value="import">Import</v-tab>
+      <v-tab value="maintenance">Maintenance</v-tab>
     </v-tabs>
 
     <v-window v-model="tab">
@@ -26,6 +27,10 @@
         <v-divider class="my-6" />
         <ImportTaskList />
       </v-window-item>
+
+      <v-window-item value="maintenance">
+        <MaintenancePanel />
+      </v-window-item>
     </v-window>
   </v-container>
 </template>
@@ -38,10 +43,13 @@ import SystemStatsCards from '../components/settings/SystemStatsCards.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 { useMLStore } from '../stores/ml.js'
 
 const tab = ref('overview')
 const system = useSystemStore()
 const importStore = useImportStore()
+const mlStore = useMLStore()
 
 let pollId = null
 
@@ -72,6 +80,8 @@ watch(tab, (t) => {
   if (t === 'import') {
     importStore.refreshStatus()
     importStore.loadTasks(true)
+  } else if (t === 'maintenance') {
+    mlStore.loadSettings()
   }
 })
 </script>