fix: --sample 0 no longer panics; avoid needless corpus clone

src/bin/alpha_id.rs

@@ -60,18 +60,17 @@ fn main() {
                 .expect("ionos client (token?)");
             let store = EmbeddingStore::open(&cfg.index_dir, &cfg.embed_model).expect("store");
 
-            let subset: Vec<String> = match sample {
-                Some(n) => texts.iter().take(n).cloned().collect(),
-                None => texts.clone(),
-            };
-
-            if sample.is_some() {
+            if let Some(n) = sample {
+                let subset: Vec<String> = texts.iter().take(n).cloned().collect();
                 let est = estimate(&subset);
                 eprintln!("SMOKE: embedding {} sample texts ({} chars)…", est.items, est.chars);
-                let n = build_corpus_embeddings(&client, &store, &cfg.embed_model, &subset, 32)
+                let n_done = build_corpus_embeddings(&client, &store, &cfg.embed_model, &subset, 32)
                     .expect("sample embed failed");
-                let dim = store.get(&subset[0]).map(|v| v.len()).unwrap_or(0);
-                eprintln!("SMOKE OK: embedded {n}, vector dim = {dim}. \
+                let dim = subset.first()
+                    .and_then(|t| store.get(t))
+                    .map(|v| v.len())
+                    .unwrap_or(0);
+                eprintln!("SMOKE OK: embedded {n_done}, vector dim = {dim}. \
                            Inspect, then run `index --full --confirm`.");
                 return;
             }