feat(import-ui): deep scan button, sticky settings tabs, tasks-above-filters, fix Scanning-undefined source_path — Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend/src/components/settings/ImportTriggerPanel.vue

@@ -7,7 +7,8 @@
           indeterminate color="accent" size="20"
         />
         <span>
-          Scanning {{ store.activeBatch.source_path }} —
+          {{ store.activeBatch.scan_mode === 'deep' ? 'Deep scanning' : 'Scanning' }}
+          {{ store.activeBatch.source_path || '/import' }} —
           imported {{ store.activeBatch.imported }},
           skipped {{ store.activeBatch.skipped }},
           failed {{ store.activeBatch.failed }} /
@@ -24,8 +25,12 @@
 
       <p class="text-body-2 mb-3">
         <span v-if="!store.activeBatch">
-          Run a quick scan of the import directory. Deep scan (pHash dedup,
-          archives) lands in FC-2d.
+          <strong>Quick scan</strong> walks <code>/import</code> and enqueues
+          new files only (skips paths already on a non-failed ImportTask).
+          <strong>Deep scan</strong> additionally chains a phash backfill
+          across the existing library — use after bulk-imports to catch
+          near-duplicates that slipped through. Both modes route non-media
+          + sidecar pairs through PostAttachment capture.
         </span>
         <span v-else>
           An active batch is in progress. Wait for it to finish, or click
@@ -34,15 +39,26 @@
         </span>
       </p>
 
-      <v-btn
-        color="primary" rounded="pill"
-        :disabled="!!store.activeBatch"
-        :loading="busy"
-        @click="trigger"
-      >
-        <v-icon start>mdi-magnify-scan</v-icon>
-        Quick scan
-      </v-btn>
+      <div class="d-flex flex-wrap" style="gap: 12px;">
+        <v-btn
+          color="primary" rounded="pill"
+          :disabled="!!store.activeBatch"
+          :loading="busy === 'quick'"
+          @click="trigger('quick')"
+        >
+          <v-icon start>mdi-magnify-scan</v-icon>
+          Quick scan
+        </v-btn>
+        <v-btn
+          color="secondary" rounded="pill" variant="tonal"
+          :disabled="!!store.activeBatch"
+          :loading="busy === 'deep'"
+          @click="trigger('deep')"
+        >
+          <v-icon start>mdi-magnify-plus-outline</v-icon>
+          Deep scan
+        </v-btn>
+      </div>
 
       <v-alert v-if="store.triggerError" type="error" variant="tonal" class="mt-3" closable>
         {{ store.triggerError }}
@@ -56,12 +72,12 @@ import { ref } from 'vue'
 import { useImportStore } from '../../stores/import.js'
 
 const store = useImportStore()
-const busy = ref(false)
+const busy = ref(null)
 const clearing = ref(false)
 
-async function trigger() {
-  busy.value = true
-  try { await store.triggerScan() } catch {} finally { busy.value = false }
+async function trigger(mode) {
+  busy.value = mode
+  try { await store.triggerScan(mode) } catch {} finally { busy.value = null }
 }
 
 async function onClearStuck() {