Baseline: full tree snapshot after git repository loss

The previous .git directory was found gutted (only info/ remained), so
history is unrecoverable locally. This commit restores version control
with the tree exactly as it stands: the working app, the preview-tracks
launcher on the artist hero, the scrollable-track-previews design bundle
(docs + approved mockups), and the Phase 0 validation artifacts.

crates/metadata/examples/lookup.rs

@@ -0,0 +1,33 @@
+//! Live check: MusicBrainz lookup + art fetch.
+//!   cargo run -p metadata --example lookup -- "Nirvana" "Nevermind"
+
+#[tokio::main]
+async fn main() {
+    let artist = std::env::args().nth(1).unwrap_or_else(|| "Nirvana".into());
+    let album = std::env::args()
+        .nth(2)
+        .unwrap_or_else(|| "Nevermind".into());
+
+    let client = metadata::MetadataClient::new();
+    match client.lookup_album(&artist, &album).await {
+        Some(meta) => {
+            println!(
+                "MB: {} — {} ({:?}) mbid={:?}",
+                meta.artist, meta.album, meta.year, meta.release_mbid
+            );
+            match client
+                .fetch_art(
+                    meta.release_mbid.as_deref(),
+                    meta.release_group_mbid.as_deref(),
+                    &meta.artist,
+                    &meta.album,
+                )
+                .await
+            {
+                Some(bytes) => println!("ART: {} bytes (starts {:02x?})", bytes.len(), &bytes[..4]),
+                None => println!("ART: none found"),
+            }
+        }
+        None => println!("MB: no match"),
+    }
+}