refactor(artist-detail): G.85 — extract Hero + TopTracks + SimilarArtists + action utilities (cluster) (#652)

Four-cut cluster closing out the major ArtistDetail extraction.
707 → 339 LOC (−368).

ArtistDetailHero — the full hero header: back button, lightbox
trigger, avatar with hover upload overlay + camera/loader icon +
hidden file input, glow effect from extractCoverColors onLoad,
title + album count, entity-rating row, Last.fm + Wikipedia +
favourite link row, and the action button strip (play all,
shuffle, radio, share, offline cache with progress / done state).
Subscribes to useOfflineStore / useOfflineJobStore / useAuthStore
directly so the page doesn't have to thread bulk-progress through.

ArtistDetailTopTracks — the four-column tracklist with each row's
inline play-next + preview ring + track cover thumbnail + click
into playTopSongWithContinuation. Subscribes to playerStore /
previewStore / useOrbitSongRowBehavior directly.

ArtistDetailSimilarArtists — section header (with show-more toggle
on mobile), loading spinner, and the chip list (using
serverSimilarArtists vs. similarArtists depending on which path
fed it).

runArtistDetailActions — four parameterized async actions:
runArtistEntityRating (with full / track_only fallback +
saveFailed toast), runArtistToggleStar (optimistic state + revert
on error), runArtistShare (copy link + success / failure toast),
runArtistImageUpload (upload + invalidate cover-art cache + bump
revision).

ArtistDetail drops the inline definitions; formatDuration moves
into the TopTracks component. Pure code move otherwise.

src/utils/runArtistDetailActions.ts

@@ -0,0 +1,115 @@
+import type React from 'react';
+import type { TFunction } from 'i18next';
+import { uploadArtistImage } from '../api/subsonicPlaylists';
+import { setRating, star, unstar } from '../api/subsonicStarRating';
+import type { SubsonicArtist } from '../api/subsonicTypes';
+import { useAuthStore } from '../store/authStore';
+import { copyEntityShareLink } from './copyEntityShareLink';
+import { invalidateCoverArt } from './imageCache';
+import { showToast } from './toast';
+
+export interface RunArtistEntityRatingDeps {
+  artist: SubsonicArtist | null;
+  id: string | undefined;
+  rating: number;
+  artistEntityRatingSupport: string;
+  activeServerId: string;
+  t: TFunction;
+  setArtistEntityRating: (v: number) => void;
+  setArtist: React.Dispatch<React.SetStateAction<SubsonicArtist | null>>;
+}
+
+export async function runArtistEntityRating(deps: RunArtistEntityRatingDeps): Promise<void> {
+  const { artist, id, rating, artistEntityRatingSupport, activeServerId, t, setArtistEntityRating, setArtist } = deps;
+  if (!artist || artist.id !== id) return;
+  const artistId = artist.id;
+  const ratingAtStart = artist.userRating ?? 0;
+
+  setArtistEntityRating(rating);
+
+  if (artistEntityRatingSupport !== 'full') return;
+
+  try {
+    await setRating(artistId, rating);
+    setArtist(a => (a && a.id === artistId ? { ...a, userRating: rating } : a));
+  } catch (err) {
+    setArtistEntityRating(ratingAtStart);
+    useAuthStore.getState().setEntityRatingSupport(activeServerId, 'track_only');
+    showToast(
+      typeof err === 'string' ? err : err instanceof Error ? err.message : t('entityRating.saveFailed'),
+      4500,
+      'error',
+    );
+  }
+}
+
+export interface RunArtistToggleStarDeps {
+  artist: SubsonicArtist | null;
+  isStarred: boolean;
+  setIsStarred: React.Dispatch<React.SetStateAction<boolean>>;
+}
+
+export async function runArtistToggleStar(deps: RunArtistToggleStarDeps): Promise<void> {
+  const { artist, isStarred, setIsStarred } = deps;
+  if (!artist) return;
+  const currentlyStarred = isStarred;
+  setIsStarred(!currentlyStarred);
+  try {
+    if (currentlyStarred) await unstar(artist.id, 'artist');
+    else await star(artist.id, 'artist');
+  } catch (e) {
+    console.error('Failed to toggle star', e);
+    setIsStarred(currentlyStarred);
+  }
+}
+
+export interface RunArtistShareDeps {
+  artist: SubsonicArtist;
+  t: TFunction;
+}
+
+export async function runArtistShare(deps: RunArtistShareDeps): Promise<void> {
+  const { artist, t } = deps;
+  try {
+    const ok = await copyEntityShareLink('artist', artist.id);
+    if (ok) showToast(t('contextMenu.shareCopied'));
+    else showToast(t('contextMenu.shareCopyFailed'), 4000, 'error');
+  } catch {
+    showToast(t('contextMenu.shareCopyFailed'), 4000, 'error');
+  }
+}
+
+export interface RunArtistImageUploadDeps {
+  e: React.ChangeEvent<HTMLInputElement>;
+  artist: SubsonicArtist | null;
+  t: TFunction;
+  setUploading: (v: boolean) => void;
+  setCoverRevision: React.Dispatch<React.SetStateAction<number>>;
+}
+
+export async function runArtistImageUpload(deps: RunArtistImageUploadDeps): Promise<void> {
+  const { e, artist, t, setUploading, setCoverRevision } = deps;
+  const file = e.target.files?.[0];
+  e.target.value = '';
+  if (!file || !artist) return;
+  setUploading(true);
+  try {
+    await uploadArtistImage(artist.id, file);
+    const coverId = artist.coverArt || artist.id;
+    await invalidateCoverArt(coverId);
+    // Also invalidate with bare artist.id in case coverArt differs
+    if (artist.coverArt && artist.coverArt !== artist.id) {
+      await invalidateCoverArt(artist.id);
+    }
+    setCoverRevision(r => r + 1);
+    showToast(t('artistDetail.uploadImage'));
+  } catch (err) {
+    showToast(
+      typeof err === 'string' ? err : err instanceof Error ? err.message : t('artistDetail.uploadImageError'),
+      4000,
+      'error',
+    );
+  } finally {
+    setUploading(false);
+  }
+}