faces: avoid 40 MB row clone in /faces/embeddings

list_embeddings cloned the full FaceDetectionRow inside the filter_map
just to pair it with the base64-encoded embedding. The 2 KB BLOB was
already on the row — at 20k unassigned faces that's 40 MB of pointless
heap traffic per Apollo cluster-suggest run. Move the bytes out via
Option::take() so the row drops the BLOB instead of duplicating it.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/faces.rs

@@ -884,14 +884,18 @@ impl FaceDao for SqliteFaceDao {
             // Pair with the base64-encoded embedding string so the handler
             // doesn't need to know the wire format. Skip rows with NULL
             // embedding (shouldn't happen on detected rows, but defensive).
+            // `embedding.take()` moves the bytes out of the row so we can
+            // hand the (now-empty-embedding) row plus the encoded string
+            // back to the caller without cloning the whole row — at 20k
+            // rows × 2 KB that clone was 40 MB of pointless heap traffic
+            // per cluster-suggest run.
             use base64::Engine;
             Ok(rows
                 .into_iter()
-                .filter_map(|r| {
-                    r.embedding.as_ref().map(|bytes| {
-                        let b64 = base64::engine::general_purpose::STANDARD.encode(bytes);
-                        (r.clone(), b64)
-                    })
+                .filter_map(|mut r| {
+                    let bytes = r.embedding.take()?;
+                    let b64 = base64::engine::general_purpose::STANDARD.encode(&bytes);
+                    Some((r, b64))
                 })
                 .collect())
         })