feat(patreon): recovery UI + gallery-dl cutover — build step 5 (plan #697)

Final step of the native Patreon ingester: a first-class Recovery action,
and removal of the now-dead gallery-dl Patreon path.

Recovery (rules #23/#24/#27 — full product, with UI):
- source_service.start_recovery arms the #693 backfill state machine PLUS
  `_backfill_bypass_seen`, flipping download mode to recovery (bypass the
  seen-ledger to re-fetch dropped-and-deleted near-dups and re-evaluate
  under the current pHash threshold). Stop via the shared stop_backfill.
- SourceRecord exposes backfill_bypass_seen; POST /sources/{id}/backfill
  gains action="recover".
- Frontend: Recovery button (Patreon-only, mdi-backup-restore) on SourceRow
  + SourceCard; the running badge labels "Recovering (N)" vs "Backfilling
  (N)"; the Stop tooltip says "Stop recovery". sources.js recoverSource +
  SubscriptionsTab onRecover.

Cutover (rule #22 — no legacy):
- gallery_dl: removed PLATFORM_DEFAULTS["patreon"], the patreon
  files/cursor branch in _build_config_for_source, and the patreon/Mux
  yt-dlp Referer/Origin block (was patreon-specific and wrongly tagged the
  other platforms' yt-dlp fetches; native ingester owns it now).
- download_service: removed the dead campaign-id-retry helpers
  (_looks_like_campaign_id_failure / _CAMPAIGN_ID_FAILURE_PATTERN) and
  _effective_url. Vanity→campaign resolution + resume_cursor + the
  cursor/PARTIAL lifecycle stay — they serve the native ingester.

Tests: removed the two obsolete patreon-gallery-dl config tests (yt-dlp
Referer, resume-cursor); repointed the generic skip-value config tests to
subscribestar; added start_recovery + recover-endpoint coverage
(backfill_bypass_seen). gallery-dl stays for the other 5 platforms.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/components/subscriptions/SourceCard.vue

@@ -27,7 +27,8 @@
       <v-chip
         v-else-if="source.backfill_state === 'running'"
         size="x-small" color="info" variant="tonal" label
-      >Backfilling{{ source.backfill_chunks ? ` (${source.backfill_chunks})` : '' }}</v-chip>
+      >{{ source.backfill_bypass_seen ? 'Recovering' : 'Backfilling'
+        }}{{ source.backfill_chunks ? ` (${source.backfill_chunks})` : '' }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
         size="x-small" color="success" variant="tonal" label
@@ -53,7 +54,19 @@
       >
         <v-icon>{{ source.backfill_state === 'running' ? 'mdi-stop' : 'mdi-magnify-scan' }}</v-icon>
         <v-tooltip activator="parent" location="top">
-          {{ source.backfill_state === 'running' ? 'Stop backfill' : 'Backfill full history' }}
+          {{ source.backfill_state === 'running'
+            ? (source.backfill_bypass_seen ? 'Stop recovery' : 'Stop backfill')
+            : 'Backfill full history' }}
+        </v-tooltip>
+      </v-btn>
+      <v-btn
+        v-if="source.platform === 'patreon' && source.backfill_state !== 'running'"
+        size="x-small" variant="text"
+        @click.stop="$emit('recover', source)"
+      >
+        <v-icon>mdi-backup-restore</v-icon>
+        <v-tooltip activator="parent" location="top">
+          Recover — re-fetch dropped near-dups &amp; re-evaluate under the current threshold
         </v-tooltip>
       </v-btn>
       <v-btn size="x-small" variant="text" @click.stop="$emit('edit', source)">
@@ -83,7 +96,7 @@ const props = defineProps({
   checking: { type: Boolean, default: false },
   warningThreshold: { type: Number, default: 5 },
 })
-const emit = defineEmits(['edit', 'remove', 'toggle', 'check', 'backfill'])
+const emit = defineEmits(['edit', 'remove', 'toggle', 'check', 'backfill', 'recover'])
 
 function onToggleEnabled(value) {
   emit('toggle', { source: props.source, enabled: value })

frontend/src/components/subscriptions/SourceRow.vue

@@ -34,7 +34,8 @@
       <v-chip
         v-else-if="source.backfill_state === 'running'"
         size="x-small" color="info" variant="tonal" label
-      >Backfilling{{ source.backfill_chunks ? ` (${source.backfill_chunks})` : '' }}</v-chip>
+      >{{ source.backfill_bypass_seen ? 'Recovering' : 'Backfilling'
+        }}{{ source.backfill_chunks ? ` (${source.backfill_chunks})` : '' }}</v-chip>
       <v-chip
         v-else-if="source.backfill_state === 'complete'"
         size="x-small" color="success" variant="tonal" label
@@ -62,10 +63,20 @@
         <v-icon>{{ source.backfill_state === 'running' ? 'mdi-stop' : 'mdi-magnify-scan' }}</v-icon>
         <v-tooltip activator="parent" location="top">
           {{ source.backfill_state === 'running'
-            ? 'Stop backfill'
+            ? (source.backfill_bypass_seen ? 'Stop recovery' : 'Stop backfill')
             : 'Backfill — walk the full post history until complete' }}
         </v-tooltip>
       </v-btn>
+      <v-btn
+        v-if="source.platform === 'patreon' && source.backfill_state !== 'running'"
+        size="x-small" variant="text"
+        @click.stop="$emit('recover', source)"
+      >
+        <v-icon>mdi-backup-restore</v-icon>
+        <v-tooltip activator="parent" location="top">
+          Recover — re-fetch dropped near-dups &amp; re-evaluate under the current threshold
+        </v-tooltip>
+      </v-btn>
       <v-btn
         icon="mdi-pencil" size="x-small" variant="text"
         @click.stop="$emit('edit', source)"
@@ -93,7 +104,7 @@ const props = defineProps({
   checking: { type: Boolean, default: false },
   warningThreshold: { type: Number, default: 5 },
 })
-const emit = defineEmits(['edit', 'remove', 'toggle', 'check', 'backfill'])
+const emit = defineEmits(['edit', 'remove', 'toggle', 'check', 'backfill', 'recover'])
 
 function onToggleEnabled(value) {
   emit('toggle', { source: props.source, enabled: value })

frontend/src/components/subscriptions/SubscriptionsTab.vue

@@ -175,6 +175,7 @@
                     @toggle="toggleSourceEnabled"
                     @check="onCheck"
                     @backfill="onBackfill"
+                    @recover="onRecover"
                   />
                   <tr v-if="item.sources.length === 0">
                     <td colspan="8" class="fc-subs__sources-empty">
@@ -251,6 +252,7 @@
             @toggle="toggleSourceEnabled"
             @check="onCheck"
             @backfill="onBackfill"
+            @recover="onRecover"
           />
           <div v-if="item.sources.length === 0" class="fc-subs__sources-empty">
             No sources yet. Tap + to add one.
@@ -554,6 +556,22 @@ async function onBackfill(source) {
   }
 }
 
+// Plan #697: arm a recovery walk (Patreon-only) — re-fetches dropped-and-deleted
+// near-dups and re-evaluates them under the current pHash threshold. Reuses the
+// backfill lifecycle/badge; stop via the same Stop control (onBackfill).
+async function onRecover(source) {
+  try {
+    await store.recoverSource(source.id, source.artist_id)
+    toast({ text: `Recovery started for ${source.artist_name}`, type: 'success' })
+    await store.loadAll()
+  } catch (e) {
+    toast({
+      text: `Recovery start failed: ${e?.detail || e?.message || e}`,
+      type: 'error',
+    })
+  }
+}
+
 async function checkAll(group) {
   let ok = 0
   let conflict = 0

frontend/src/stores/sources.js

@@ -98,6 +98,14 @@ export const useSourcesStore = defineStore('sources', () => {
     _invalidate(artistIdHint ?? body.artist_id)
     return body
   }
+  // Plan #697: arm a recovery walk — a backfill that bypasses the Patreon
+  // seen-ledger to re-fetch dropped-and-deleted near-dups and re-evaluate them
+  // under the current pHash threshold. Stop with stopBackfill (shared lifecycle).
+  async function recoverSource(id, artistIdHint = null) {
+    const body = await api.post(`/api/sources/${id}/backfill`, { body: { action: 'recover' } })
+    _invalidate(artistIdHint ?? body.artist_id)
+    return body
+  }
 
   function sourcesByArtistGrouped() {
     // returns [{artist: {id,name,slug}, sources: [...]}, ...]
@@ -127,6 +135,7 @@ export const useSourcesStore = defineStore('sources', () => {
     checkNow,
     startBackfill,
     stopBackfill,
+    recoverSource,
     findOrCreateArtist, autocompleteArtist,
     loadScheduleStatus,
     sourcesByArtistGrouped,