feat(identity): web metadata enrichment for titles missing on TMDB (META-1)

- metadata.enrich (propose, low, replay safe): normalized-title cache (kv_cache
  region enrich, 7 days) -> daily budget -> web.search (title + 短剧 / 电视剧 平台,
  second query limited to whitelist via site:) -> web.fetch of up to 3 relevant
  whitelisted pages (registered site domains never read, redirects out of the
  whitelist dropped) -> upstream model extraction with rule fallback -> server-side
  evidence check (rule_confirmed / multi_evidence / needs_review). Suggestion only.
- POST /identity-pool/{id}/enrich (suggest) and /enrich/apply (console session):
  provisional entity or same-title merge, season/episode units, field-level
  metadata with source web/agent + evidence, aliases, release assignment.
  Poster proxy GET /img/enrich/{id} (og:image from whitelisted pages only).
- Auto-enrich once per pool entry when subscription/rule lookups find nothing on
  TMDB (identity.autoEnrich, off by default); identity.enrichDailyBudget,
  identity.enrichDomains settings; web.fetch now returns og:image.
- Pool sheet "元数据补全" section; entity detail shows evidence links.
- Migration 0049_enrichment (metadata_enrichment, metadata_field.evidence, source
  web). Requires image rebuild / api + worker restart to take effect.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/library/identity-pool-sheet.tsx

@@ -15,6 +15,7 @@ import { Input } from "~/components/ui/input.tsx";
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "~/components/ui/select.tsx";
 import { errorMessage } from "~/lib/api.ts";
 import { formatDateTime } from "~/lib/utils.ts";
+import { EnrichSection } from "./identity-enrich.tsx";
 import { EVIDENCE_LEVEL, POOL_REASON, POOL_STATUS } from "./labels.ts";
 import { Chip, Tone } from "./parts.tsx";
 
@@ -243,6 +244,10 @@ export function PoolSheet({ item, onClose }: { item: IdentityPoolItem | null; on
 
       {item.status !== "resolved" && !queued ? <ManualAssign item={item} /> : null}
 
+      {item.status === "pending" && item.reason !== "ambiguous" && item.reason !== "proposed" ? (
+        <EnrichSection key={item.id} item={item} />
+      ) : null}
+
       <DetailSection title={`候选(${item.candidates.length})`}>
         {item.candidates.length ? (
           <ul className="space-y-2">