feat(album): show OpenSubsonic disc subtitles after the CD heading (#753)

* feat(album): show OpenSubsonic disc subtitles after the CD heading

Multi-disc albums in OpenSubsonic / Navidrome carry a per-disc
subtitle (`discTitles`) — e.g. "Sessions" on CD 3 of a deluxe
edition. AlbumTrackList only rendered "CD N" and dropped the
subtitle, so users couldn't tell two discs apart unless they read
the track names.

* `SubsonicAlbum.discTitles` typed; `getAlbum` forwards it as-is.
* `AlbumTrackList` and `AlbumTrackListMobile` take a discTitleByNum
  map and render the subtitle in the disc separator after "CD N".
* Heading bumped slightly (13 → 15 px, icon 16 → 18 px) so the disc
  separator stays legible next to the new subtitle.

* docs(changelog): note disc subtitles after CD heading (#753)

CHANGELOG.md

@@ -216,6 +216,12 @@ Foundational work: faster reviews, narrower diffs, and a safety net under the pa
 
 * The Queue side panel's ETA label and the sleep-timer preview both go through **`formatClockTime`**, which just delegates to **`toLocaleTimeString`** — on en-US that meant AM/PM with no in-app override. **Settings → System → App Behavior** now exposes a tri-state **Clock Format** select: **`Auto`** (default — keeps existing locale-driven behaviour, so first launch after the update is a no-op for everyone), **`24h`**, and **`12h`**, the explicit values forcing **`hour12`** everywhere `formatClockTime` is used. Wired through `authStore` (`clockFormat` / `setClockFormat`) and consumed by both surfaces; all nine bundled locales ship the four new strings.
 
+### Album page — OpenSubsonic disc subtitles after the CD heading
+
+**By [@Psychotoxical](https://github.com/Psychotoxical), thanks to zunoz for the report on the Psysonic Discord, PR [#753](https://github.com/Psychotoxical/psysonic/pull/753)**
+
+* Multi-disc albums in OpenSubsonic / Navidrome can carry a per-disc subtitle (`discTitles`, e.g. **"Sessions"** on CD 3 of a deluxe edition). The album tracklist previously dropped it and only showed **`CD N`**, so adjacent discs of a reissue read the same in the header. The disc separator now renders **`CD N — Subtitle`** in both desktop and mobile track lists, and the heading is bumped slightly so the subtitle stays legible next to the disc number.
+
 ## Changed
 
 ### Backend — Cargo workspace with 5 domain crates (Rust refactor)

src/api/subsonicTypes.ts

@@ -22,6 +22,13 @@ export interface SubsonicAlbum {
   releaseTypes?: string[];
   /** OpenSubsonic: album-level credits (Navidrome may attach on album and/or child songs). */
   albumArtists?: SubsonicOpenArtistRef[];
+  /** OpenSubsonic: per-disc subtitles (e.g. "Sessions" on CD 3 of a deluxe edition). */
+  discTitles?: SubsonicDiscTitle[];
+}
+
+export interface SubsonicDiscTitle {
+  disc: number;
+  title: string;
 }
 
 /** OpenSubsonic `artists` / `albumArtists` entries on a child song (may include `userRating`). */

src/components/AlbumTrackList.tsx

@@ -20,6 +20,8 @@ export type { SortKey } from '../utils/componentHelpers/albumTrackListHelpers';
 
 interface AlbumTrackListProps {
   songs: SubsonicSong[];
+  /** Per-disc subtitles from the album payload, rendered after "CD N". */
+  discTitles?: { disc: number; title: string }[];
   sorted?: boolean;
   hasVariousArtists: boolean;
   currentTrack: Track | null;
@@ -42,6 +44,7 @@ interface AlbumTrackListProps {
 
 export default function AlbumTrackList({
   songs,
+  discTitles,
   sorted,
   hasVariousArtists: _hasVariousArtists,
   currentTrack,
@@ -90,6 +93,9 @@ export default function AlbumTrackList({
   }
   const discNums = sorted ? [1] : Array.from(discs.keys()).sort((a, b) => a - b);
   const isMultiDisc = !sorted && discNums.length > 1;
+  const discTitleByNum = new Map<number, string>(
+    (discTitles ?? []).filter(d => d.title?.trim()).map(d => [d.disc, d.title.trim()]),
+  );
 
   const currentTrackId = currentTrack?.id ?? null;
 
@@ -98,6 +104,7 @@ export default function AlbumTrackList({
       <AlbumTrackListMobile
         discNums={discNums}
         discs={discs}
+        discTitleByNum={discTitleByNum}
         isMultiDisc={isMultiDisc}
         currentTrackId={currentTrackId}
         isPlaying={isPlaying}
@@ -150,6 +157,9 @@ export default function AlbumTrackList({
             <div className="disc-header">
               <span className="disc-icon">💿</span>
               CD {discNum}
+              {discTitleByNum.get(discNum) && (
+                <span className="disc-subtitle">{discTitleByNum.get(discNum)}</span>
+              )}
             </div>
           )}
           {discs.get(discNum)!.map(song => {

src/components/albumTrackList/AlbumTrackListMobile.tsx

@@ -8,6 +8,7 @@ import { formatLongDuration } from '../../utils/format/formatDuration';
 interface Props {
   discNums: number[];
   discs: Map<number, SubsonicSong[]>;
+  discTitleByNum: Map<number, string>;
   isMultiDisc: boolean;
   currentTrackId: string | null;
   isPlaying: boolean;
@@ -31,6 +32,7 @@ interface Props {
 export function AlbumTrackListMobile({
   discNums,
   discs,
+  discTitleByNum,
   isMultiDisc,
   currentTrackId,
   isPlaying,
@@ -46,6 +48,9 @@ export function AlbumTrackListMobile({
           {isMultiDisc && (
             <div className="disc-header">
               <span className="disc-icon">💿</span> CD {discNum}
+              {discTitleByNum.get(discNum) && (
+                <span className="disc-subtitle">{discTitleByNum.get(discNum)}</span>
+              )}
             </div>
           )}
           {discs.get(discNum)!.map(song => {

src/pages/AlbumDetail.tsx

@@ -341,6 +341,7 @@ const handleShuffleAll = () => {
 
       <AlbumTrackList
         songs={displayedSongs}
+        discTitles={album?.album.discTitles}
         sorted={sortKey !== 'natural' || !!filterText.trim()}
         hasVariousArtists={hasVariousArtists}
         currentTrack={currentTrack}

src/styles/components/tracklist.css

@@ -536,7 +536,7 @@ html[data-track-previews-randommix="off"]   [data-preview-loc="randomMix"]   .pl
   gap: var(--space-3);
   padding: var(--space-4) var(--space-3) var(--space-2);
   font-family: var(--font-display);
-  font-size: 13px;
+  font-size: 15px;
   font-weight: 700;
   letter-spacing: 0.06em;
   text-transform: uppercase;
@@ -551,7 +551,19 @@ html[data-track-previews-randommix="off"]   [data-preview-loc="randomMix"]   .pl
 }
 
 .disc-icon {
-  font-size: 16px;
+  font-size: 18px;
+}
+
+/* Per-disc subtitle (OpenSubsonic `discTitles`), e.g. "Sessions" on a deluxe CD 3. */
+.disc-subtitle {
+  color: var(--text-muted);
+  font-weight: 600;
+  letter-spacing: 0.04em;
+}
+.disc-subtitle::before {
+  content: '— ';
+  margin-right: 2px;
+  color: var(--text-muted);
 }