feat(library): surface metadata enrichment status, errors and covers

The mapper dropped metadata_status and hardcoded availability, so enrichment
state was invisible and a just-uploaded track never appeared to change. Map
metadata_status/metadata_error/has_cover onto Track; add MetadataStatusBadge
(pending spinner / enriched / failed-with-reason / manual) shown in TrackRow,
and serve token-bearing track covers via getTrackCoverUrl.

UploadPage now polls each uploaded track (stops once enrichment settles) so the
resolved title/artist — or a failure reason — appears live. i18n in en + ru.

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

src/api/endpoints/streaming.ts

@@ -17,3 +17,18 @@ export function getCoverUrl(artUrl: string | undefined): string | undefined {
   const base = getApiBaseUrl();
   return `${base}${artUrl}`;
 }
+
+/**
+ * Cover image URL for a track, served by `GET /tracks/{id}/cover`. Like the
+ * audio stream, an `<img>` can't send an `Authorization` header, so the access
+ * token rides as `?token=`. Returns undefined when the track has no cover.
+ */
+export function getTrackCoverUrl(
+  trackId: string,
+  token: string,
+  hasCover: boolean,
+): string | undefined {
+  if (!hasCover) return undefined;
+  const base = getApiBaseUrl();
+  return `${base}/tracks/${trackId}/cover?token=${encodeURIComponent(token)}`;
+}

src/api/mappers.ts

@@ -14,12 +14,27 @@
 import type {
   Album,
   Artist,
+  MetadataStatus,
   PaginatedResponse,
   Playlist,
   Track,
   User,
 } from './types';
 
+const METADATA_STATUSES: readonly MetadataStatus[] = [
+  'pending',
+  'enriched',
+  'failed',
+  'manual',
+];
+
+/** Map the backend's free-form status string onto the UI union, defaulting any
+ * unknown value to `pending` (a safe "not yet identified" state). */
+const toMetadataStatus = (raw: string): MetadataStatus =>
+  (METADATA_STATUSES as readonly string[]).includes(raw)
+    ? (raw as MetadataStatus)
+    : 'pending';
+
 // ---- raw wire shapes (snake_case, exactly as the backend emits) ----
 
 export interface RawPaged<T> {
@@ -49,6 +64,9 @@ export interface RawTrack {
   file_format: string;
   file_size: number;
   metadata_status: string;
+  metadata_error: string | null;
+  enriched_at: string | null;
+  has_cover: boolean;
   source: string;
   created_at: string;
 }
@@ -98,13 +116,17 @@ export const toTrack = (r: RawTrack): Track => ({
   artistName: r.artist_name,
   albumId: r.album_id ?? '',
   albumTitle: r.album_title ?? '',
-  // Cover endpoints aren't wired on the backend yet — leave art undefined so the
-  // UI renders generated tile art instead of a broken image.
+  // `has_cover` says a cover exists; the actual URL (which needs a `?token=`) is
+  // built in the component from the track id — see `getTrackCoverUrl`. Keep
+  // `albumArtUrl` undefined so callers fall back to generated tile art.
   albumArtUrl: undefined,
+  hasCover: r.has_cover,
   durationMs: (r.duration_seconds ?? 0) * 1000,
   // The lean TrackOut carries no availability/like state: a track returned by
   // the library is on the server, and per-track like state comes from /likes.
   availability: 'server',
+  metadataStatus: toMetadataStatus(r.metadata_status),
+  metadataError: r.metadata_error ?? undefined,
   liked: false,
   format: r.file_format,
   fileSize: r.file_size,

src/api/types.ts

@@ -1,5 +1,13 @@
 export type TrackAvailability = 'server' | 'downloading' | 'error' | 'missing';
 
+/**
+ * Metadata-enrichment state, distinct from file `availability`. `pending` = the
+ * worker hasn't finished (or hasn't started); `enriched` = identity found;
+ * `failed` = no match / a worker error (see `metadataError`); `manual` = user-
+ * edited and never auto-overwritten.
+ */
+export type MetadataStatus = 'pending' | 'enriched' | 'failed' | 'manual';
+
 export interface Track {
   id: string;
   title: string;
@@ -8,12 +16,16 @@ export interface Track {
   albumId: string;
   albumTitle: string;
   albumArtUrl?: string;
+  hasCover: boolean;
   durationMs: number;
   trackNumber?: number;
   discNumber?: number;
   year?: number;
   genre?: string;
   availability: TrackAvailability;
+  metadataStatus: MetadataStatus;
+  /** Human-readable reason the last enrichment run set `failed`; else undefined. */
+  metadataError?: string;
   fileSize?: number;
   format?: string;
   bitrate?: number;