feat(ingest): Recapture mode — re-grab post bodies/links + localize on-disk inline images (#830)

A plain backfill gates post-body capture on the seen-ledger, so a post whose
media is already on disk AND whose post key is already seen never gets its body
recaptured (operator-flagged: Industrial Lust description missing). Recovery
recaptures unconditionally but re-downloads the whole source.

New 'recapture' walk mode (4th beside tick/backfill/recovery): bypasses the
post-record gate so EVERY post's body + external links are re-captured
(detail-fetching empty bodies) WITHOUT re-downloading on-disk media; and
surfaces already-present media via a separate non-deleting relink channel so the
importer backfills ImageRecord.source_filehash for inline-image localization.

- ingest_core: recapture mode + recapture_records gate bypass + relink collect
- patreon_downloader: recapture surfaces seen-on-disk as skipped_disk(path),
  never refetches seen-missing media, still downloads genuinely-new
- importer.relink_source_filehash: NULL-only sha256 backfill, never unlinks
- download_service: mode derivation + phase-3 relink loop + lifecycle clear
- source_service/api: start_recapture + backfill_recapture field + action
- frontend: Recapture kebab action + 'Recapturing' badge across SourceActions/
  Row/Card/SubscriptionsTab + sources store
- tests across ingester/downloader/importer/source_service/api/download_service

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/components/subscriptions/SourceActions.vue

@@ -21,7 +21,7 @@
       <v-icon>{{ running ? 'mdi-stop' : 'mdi-magnify-scan' }}</v-icon>
       <v-tooltip activator="parent" location="top">
         {{ running
-          ? (recovering ? 'Stop recovery' : 'Stop backfill')
+          ? (recovering ? 'Stop recovery' : (recapturing ? 'Stop recapture' : 'Stop backfill'))
           : 'Backfill — one-time walk of the FULL post history until complete' }}
       </v-tooltip>
     </v-btn>
@@ -38,6 +38,17 @@
           under the current similarity threshold
         </v-list-item-subtitle>
       </v-list-item>
+      <v-list-item
+        v-if="isPatreon && !running"
+        prepend-icon="mdi-text-box-search-outline"
+        @click="emit('recapture', source)"
+      >
+        <v-list-item-title>Recapture post text &amp; links</v-list-item-title>
+        <v-list-item-subtitle>
+          Re-grab every post's body + external links and localize inline images
+          already on disk — without re-downloading media
+        </v-list-item-subtitle>
+      </v-list-item>
       <v-divider v-if="isPatreon && !running" />
       <v-list-item
         base-color="error"
@@ -58,10 +69,11 @@ const props = defineProps({
   source: { type: Object, required: true },
   checking: { type: Boolean, default: false },
 })
-const emit = defineEmits(['check', 'backfill', 'recover', 'remove'])
+const emit = defineEmits(['check', 'backfill', 'recover', 'recapture', 'remove'])
 
 const running = computed(() => props.source.backfill_state === 'running')
 const recovering = computed(() => !!props.source.backfill_bypass_seen)
+const recapturing = computed(() => !!props.source.backfill_recapture)
 const isPatreon = computed(() => props.source.platform === 'patreon')
 </script>