feat(gpu): GPU agent admin card — token, queue, backfill (#114)

The FC-side control surface the operator asked for: Settings → Tagging → "GPU
agent". Generate/reveal/copy/rotate the agent bearer token (with the FC URL to
point the agent at), see the live job-queue depth (pending/in-flight/done/
errored, polled), and a "Queue character embedding (CCIP)" button that triggers
the library backfill. Plain-HTTP-safe copy (copyText resolves on success,
throws on fail). Closes the "how do I get the token in the UI" gap.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ttrj5P7upUTueSfoJcxEqa

frontend/src/components/settings/GpuAgentCard.vue

@@ -0,0 +1,166 @@
+<template>
+  <MaintenanceTile
+    icon="mdi-expansion-card"
+    title="GPU agent (CCIP + crops)"
+    blurb="Connect a desktop-GPU agent to embed characters (CCIP) and crops. It pulls work over HTTP — your database and Redis stay private."
+    :open="true"
+  >
+    <p class="fc-muted text-body-2 mb-3">
+      The agent is a container you run on the machine with the GPU. It
+      authenticates with the token below, leases jobs from this server, computes
+      on the GPU, and posts results back — all over HTTP. Start it when you want
+      a burst; stop it to reclaim the card.
+    </p>
+
+    <!-- Token -->
+    <div class="fc-section-h mb-1">Agent token</div>
+    <div v-if="loading" class="fc-muted text-body-2">Loading…</div>
+    <template v-else>
+      <div v-if="tokenValue" class="fc-token">
+        <code class="fc-token__val">{{ masked ? maskedToken : tokenValue }}</code>
+        <v-btn
+          size="x-small" variant="text" :icon="masked ? 'mdi-eye' : 'mdi-eye-off'"
+          :title="masked ? 'Reveal' : 'Hide'" @click="masked = !masked"
+        />
+        <v-btn
+          size="x-small" variant="text" icon="mdi-content-copy"
+          title="Copy token" @click="onCopy"
+        />
+        <v-btn
+          size="small" variant="text" color="accent" class="ml-auto"
+          prepend-icon="mdi-refresh" :loading="rotating" @click="onRotate"
+        >Rotate</v-btn>
+      </div>
+      <div v-else>
+        <v-btn
+          color="accent" variant="flat" rounded="pill" size="small"
+          prepend-icon="mdi-key-plus" :loading="rotating" @click="onRotate"
+        >Generate token</v-btn>
+      </div>
+      <p class="fc-muted text-caption mt-2 mb-0">
+        Point the agent at <code>{{ baseUrl }}</code> with this token. Rotating
+        invalidates the old token — update the agent after you rotate.
+      </p>
+    </template>
+
+    <!-- Queue -->
+    <div class="fc-section-h mt-5 mb-2">Work queue</div>
+    <div class="fc-queue">
+      <div class="fc-q"><div class="fc-q__n">{{ queue.pending }}</div><div class="fc-q__l">pending</div></div>
+      <div class="fc-q"><div class="fc-q__n">{{ queue.leased }}</div><div class="fc-q__l">in flight</div></div>
+      <div class="fc-q"><div class="fc-q__n fc-good">{{ queue.done }}</div><div class="fc-q__l">done</div></div>
+      <div class="fc-q"><div class="fc-q__n" :class="queue.error ? 'fc-weak' : ''">{{ queue.error }}</div><div class="fc-q__l">errored</div></div>
+    </div>
+
+    <v-btn
+      class="mt-4" color="accent" variant="tonal" rounded="pill" size="small"
+      prepend-icon="mdi-account-box-multiple" :loading="backfilling" @click="onBackfill"
+    >Queue character embedding (CCIP)</v-btn>
+    <p class="fc-muted text-caption mt-2 mb-0">
+      Enqueues every image that doesn't have a CCIP embedding yet. Nothing
+      processes until the agent is running.
+    </p>
+  </MaintenanceTile>
+</template>
+
+<script setup>
+import { toast } from '../../utils/toast.js'
+import { computed, onMounted, onUnmounted, ref } from 'vue'
+
+import MaintenanceTile from '../common/MaintenanceTile.vue'
+import { useGpuStore } from '../../stores/gpu.js'
+import { copyText } from '../../utils/clipboard.js'
+
+const store = useGpuStore()
+const loading = ref(true)
+const tokenValue = ref(null)
+const masked = ref(true)
+const rotating = ref(false)
+const backfilling = ref(false)
+const queue = ref({ pending: 0, leased: 0, done: 0, error: 0 })
+let pollTimer = null
+
+const baseUrl = computed(() => window.location.origin)
+const maskedToken = computed(() => {
+  const t = tokenValue.value || ''
+  return t.length > 8 ? `${t.slice(0, 4)}••••••••${t.slice(-4)}` : '••••••••'
+})
+
+onMounted(async () => {
+  try {
+    tokenValue.value = (await store.token()).token
+  } catch { /* non-fatal */ } finally {
+    loading.value = false
+  }
+  await refreshQueue()
+  pollTimer = setInterval(() => { if (!document.hidden) refreshQueue() }, 5000)
+})
+onUnmounted(() => { if (pollTimer) clearInterval(pollTimer) })
+
+async function refreshQueue() {
+  try { queue.value = await store.status() } catch { /* non-fatal */ }
+}
+
+async function onRotate() {
+  rotating.value = true
+  try {
+    tokenValue.value = (await store.rotateToken()).token
+    masked.value = false
+    toast({ text: 'New agent token generated — update your agent', type: 'success' })
+  } catch (e) {
+    toast({ text: `Could not rotate token: ${e.message}`, type: 'error' })
+  } finally {
+    rotating.value = false
+  }
+}
+
+async function onCopy() {
+  try {
+    await copyText(tokenValue.value || '')   // resolves on success, throws on fail
+    toast({ text: 'Token copied', type: 'success' })
+  } catch {
+    toast({ text: 'Copy failed — select and copy manually', type: 'warning' })
+  }
+}
+
+async function onBackfill() {
+  backfilling.value = true
+  try {
+    await store.backfill('ccip')
+    toast({ text: 'Queued CCIP embedding — run the agent to process it', type: 'success' })
+    await refreshQueue()
+  } catch (e) {
+    toast({ text: `Could not queue backfill: ${e.message}`, type: 'error' })
+  } finally {
+    backfilling.value = false
+  }
+}
+</script>
+
+<style scoped>
+.fc-muted { color: rgb(var(--v-theme-on-surface-variant)); }
+.fc-section-h {
+  font-size: 13px; font-weight: 700; letter-spacing: 0.03em;
+  text-transform: uppercase; color: rgb(var(--v-theme-on-surface));
+}
+.fc-token {
+  display: flex; align-items: center; gap: 4px;
+  background: rgb(var(--v-theme-surface-light)); border-radius: 6px;
+  padding: 4px 6px 4px 10px;
+}
+.fc-token__val {
+  font-family: 'JetBrains Mono', monospace; font-size: 13px;
+  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
+}
+.fc-queue { display: flex; gap: 24px; }
+.fc-q__n {
+  font-size: 20px; font-weight: 700; line-height: 1.1;
+  font-family: 'JetBrains Mono', monospace;
+}
+.fc-q__l {
+  font-size: 11px; text-transform: uppercase; letter-spacing: 0.04em;
+  color: rgb(var(--v-theme-on-surface-variant));
+}
+.fc-good { color: rgb(var(--v-theme-success)); }
+.fc-weak { color: rgb(var(--v-theme-error)); }
+</style>

frontend/src/components/settings/MaintenancePanel.vue

@@ -27,6 +27,7 @@
       <div class="fc-tile-stack">
         <MLThresholdSliders />
         <HeadsCard />
+        <GpuAgentCard />
         <AllowlistTable />
         <AliasTable />
         <TagEvalCard />
@@ -54,6 +55,7 @@ import MissingFileRepairCard from './MissingFileRepairCard.vue'
 import DbMaintenanceCard from './DbMaintenanceCard.vue'
 import MLThresholdSliders from './MLThresholdSliders.vue'
 import HeadsCard from './HeadsCard.vue'
+import GpuAgentCard from './GpuAgentCard.vue'
 import AllowlistTable from './AllowlistTable.vue'
 import AliasTable from './AliasTable.vue'
 import TagEvalCard from './TagEvalCard.vue'