feat: MusicBrainz verification badge + MBID links in track details

Track details dialog now shows:

1. Green checkmark badge next to the track title when the recording
   has a MusicBrainz ID (hover: 'Metadata verified by MusicBrainz')

2. MusicBrainz section at the bottom with clickable MBID links for:
   - Recording (track) → musicbrainz.org/recording/{mbid}
   - Release Group (album) → musicbrainz.org/release-group/{mbid}
   - Artist → musicbrainz.org/artist/{mbid}

   Links open in the system browser. Only shown for entities that
   have MBIDs from audio file tags.

Backend: GetTrackMBIDs(filePath) Wails binding queries recording,
release_group, and artist mbid columns via a single JOIN query.
Frontend: loaded async when the dialog opens, non-blocking.

frontend/src/components/track-details/track-details.ts

@@ -18,6 +18,8 @@ import {
     BatchWriteTrackTags,
     CancelBatchWrite,
 } from '@go/tagwriter/TagWriter';
+import { GetTrackMBIDs } from '@go/library/Library';
+import type { TrackMBIDs } from '@go/library/Library';
 import { ImageFilePicker, ReadFile } from '@go/frontendutil/FrontendUtil';
 import { libraryStore } from '../../store/library-store';
 import { EventsOn, EventsOff } from '@runtime/runtime';
@@ -98,6 +100,7 @@ export class TrackDetails extends LitElement {
         failures: Array<{ filePath: string; error: string }>;
     } | null = null;
     @state() private showConfirmation = false;
+    @state() private trackMBIDs: TrackMBIDs | null = null;
 
     @query('wa-dialog')
     private dialog!: HTMLElement & { open: boolean };
@@ -117,9 +120,13 @@ export class TrackDetails extends LitElement {
         this.editing = false;
         this.editValues = {};
         this.errorMessage = '';
+        this.trackMBIDs = null;
         this.cleanupPendingCoverArt();
         this.resetBatchState();
 
+        // Load MBIDs asynchronously.
+        this.loadMBIDs(track.FilePath);
+
         this.updateComplete.then(() => {
             if (this.dialog) this.dialog.open = true;
         });
@@ -316,6 +323,39 @@ export class TrackDetails extends LitElement {
             font-style: italic;
         }
 
+        /* MusicBrainz badge + links */
+        .mb-verified-badge {
+            color: #1db954;
+            font-size: 14px;
+            margin-left: 6px;
+            vertical-align: middle;
+            cursor: help;
+        }
+
+        .mb-section-header {
+            display: flex;
+            align-items: center;
+            gap: 6px;
+        }
+
+        .mb-icon {
+            color: #1db954;
+            font-size: 14px;
+        }
+
+        .mb-link {
+            font-size: var(--yj-text-xs);
+            color: var(--yj-text-secondary, #b3b3b3);
+            text-decoration: none;
+            word-break: break-all;
+            font-family: monospace;
+        }
+
+        .mb-link:hover {
+            color: #1db954;
+            text-decoration: underline;
+        }
+
         /* Edit mode inputs */
         .meta-input {
             width: 100%;
@@ -725,6 +765,7 @@ export class TrackDetails extends LitElement {
             <div class="metadata-grid">
                 ${this.renderAudioProperties(t)}
             </div>
+            ${this.renderMusicBrainzSection()}
             <div class="action-bar">
                 ${this.renderActions()}
             </div>
@@ -1297,6 +1338,14 @@ export class TrackDetails extends LitElement {
                 <label class="main-field-label">Title</label>
                 <span class="title">
                     ${t.TrackName || this.fileNameFromPath(t.FilePath)}
+                    ${this.trackMBIDs?.recordingMbid
+                        ? html`<span
+                              class="mb-verified-badge"
+                              title="Metadata verified by MusicBrainz"
+                          >
+                              <wa-icon name="circle-check"></wa-icon>
+                          </span>`
+                        : nothing}
                 </span>
             </div>
             <div class="main-field-group">
@@ -1420,6 +1469,61 @@ export class TrackDetails extends LitElement {
         );
     }
 
+    private renderMusicBrainzSection() {
+        if (!this.trackMBIDs) return nothing;
+
+        const mbids = this.trackMBIDs;
+        const links: Array<{ label: string; mbid: string; type: string }> = [];
+
+        if (mbids.recordingMbid) {
+            links.push({
+                label: 'Recording',
+                mbid: mbids.recordingMbid,
+                type: 'recording',
+            });
+        }
+
+        if (mbids.releaseGroupMbid) {
+            links.push({
+                label: 'Release Group',
+                mbid: mbids.releaseGroupMbid,
+                type: 'release-group',
+            });
+        }
+
+        if (mbids.artistMbid) {
+            links.push({
+                label: 'Artist',
+                mbid: mbids.artistMbid,
+                type: 'artist',
+            });
+        }
+
+        if (links.length === 0) return nothing;
+
+        return html`
+            <div class="section-header mb-section-header">
+                <wa-icon name="circle-check" class="mb-icon"></wa-icon>
+                MusicBrainz
+            </div>
+            <div class="metadata-grid">
+                ${links.map(
+                    (l) => html`
+                        <span class="meta-label">${l.label}</span>
+                        <a
+                            class="mb-link"
+                            href="https://musicbrainz.org/${l.type}/${l.mbid}"
+                            target="_blank"
+                            title="View on MusicBrainz"
+                        >
+                            ${l.mbid}
+                        </a>
+                    `,
+                )}
+            </div>
+        `;
+    }
+
     private renderField(f: MetadataField) {
         const display =
             this.getEditValue(f.key, f.value) || f.value;
@@ -1885,6 +1989,18 @@ export class TrackDetails extends LitElement {
         this.cleanupPendingCoverArt();
     }
 
+    private async loadMBIDs(filePath: string): Promise<void> {
+        try {
+            const mbids = await GetTrackMBIDs(filePath);
+
+            if (mbids.recordingMbid || mbids.releaseGroupMbid || mbids.artistMbid) {
+                this.trackMBIDs = mbids;
+            }
+        } catch {
+            // Non-critical — MBIDs just won't show.
+        }
+    }
+
     private cleanupPendingCoverArt(): void {
         if (this.pendingCoverArt?.previewUrl) {
             URL.revokeObjectURL(