feat(gpu): re-process trigger to apply new crop detectors to the existing library (#1202)

The siglip/ccip backfills skip images that already have current-version regions,
so adding crop detectors only affected NEW images — the back-catalogue would
never be re-cropped. Add a reprocess trigger that resets every done/error job of
a task back to pending, so the agent re-runs the FULL pipeline (figure detection
+ CCIP + concept/panel crops) over the whole library under the current detectors.

- reprocess_gpu_jobs(task='ccip') task + POST /api/gpu/reprocess.
- gpu store reprocess() + GpuAgentCard "Re-process library (re-detect + re-crop)"
  button with a confirm (it's heavy).
- Test: a done job resets to pending (attempts cleared).

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

frontend/src/components/settings/GpuAgentCard.vue

@@ -71,6 +71,16 @@
       images get these automatically; this catches the back-catalogue.
     </p>
 
+    <v-btn
+      class="mt-3" color="warning" variant="tonal" rounded="pill" size="small"
+      prepend-icon="mdi-backup-restore" :loading="reprocessing" @click="onReprocess"
+    >Re-process library (re-detect + re-crop)</v-btn>
+    <p class="fc-muted text-caption mt-2 mb-0">
+      Re-runs the FULL pipeline (figure detection + CCIP + concept/panel crops) on
+      <b>every</b> image — use after changing crop detectors so the back-catalogue
+      gets re-cropped, not just new images. Heavy: re-processes the whole library.
+    </p>
+
     <!-- Match strictness -->
     <div class="fc-section-h mt-5 mb-1">Character-match strictness</div>
     <div v-if="ml.settings" class="d-flex align-center" style="gap:12px">
@@ -157,6 +167,7 @@ const masked = ref(true)
 const rotating = ref(false)
 const backfilling = ref(false)
 const backfillingSiglip = ref(false)
+const reprocessing = ref(false)
 const threshold = ref(0.85)
 const savingThreshold = ref(false)
 const autoApply = ref(true)
@@ -307,6 +318,20 @@ async function onBackfillSiglip() {
     backfillingSiglip.value = false
   }
 }
+
+async function onReprocess() {
+  if (!window.confirm('Re-process the ENTIRE library (re-detect + re-crop every image)? This is heavy and runs on the GPU agent.')) return
+  reprocessing.value = true
+  try {
+    await store.reprocess('ccip')
+    toast({ text: 'Library queued for re-processing — run the agent to drain it', type: 'success' })
+    await refreshQueue()
+  } catch (e) {
+    toast({ text: `Could not start re-process: ${e.message}`, type: 'error' })
+  } finally {
+    reprocessing.value = false
+  }
+}
 </script>
 
 <style scoped>

frontend/src/stores/gpu.js

@@ -29,5 +29,11 @@ export const useGpuStore = defineStore('gpu', () => {
     return await api.post('/api/gpu/backfill', { body: { task } })
   }
 
-  return { token, rotateToken, status, backfill }
+  // Reset every done/error `task` job to pending → re-run the WHOLE library
+  // under the current pipeline (e.g. after adding crop detectors).
+  async function reprocess(task = 'ccip') {
+    return await api.post('/api/gpu/reprocess', { body: { task } })
+  }
+
+  return { token, rotateToken, status, backfill, reprocess }
 })