feat: progressive multi-round face matching + pending person API

- Identity agent: per-face max matching, multi-round with derived
  seeds from high-confidence faces, angle diversity filter (cosine sim < 0.90)
- Pending person API: POST /file/:file_uuid/pending-person
  + GET /file/:file_uuid/pending-persons with status=pending, source=manual
- Update API docs (07_identity.md)

src/api/identities.rs

@@ -166,18 +166,21 @@ async fn list_identities(
 
     let id_table = crate::core::db::schema::table_name("identities");
 
-    let total: i64 = sqlx::query_scalar(&format!("SELECT COUNT(*) FROM {}", id_table))
-        .fetch_one(db.pool())
-        .await
-        .map_err(|e| {
-            (
-                StatusCode::INTERNAL_SERVER_ERROR,
-                format!("Count error: {}", e),
-            )
-        })?;
+    let total: i64 = sqlx::query_scalar(&format!(
+        "SELECT COUNT(*) FROM {} WHERE status IS NULL OR status != 'merged'",
+        id_table
+    ))
+    .fetch_one(db.pool())
+    .await
+    .map_err(|e| {
+        (
+            StatusCode::INTERNAL_SERVER_ERROR,
+            format!("Count error: {}", e),
+        )
+    })?;
 
     let sql = format!(
-        "SELECT id::int, uuid, name, metadata FROM {} ORDER BY id DESC LIMIT $1 OFFSET $2",
+        "SELECT id::int, uuid, name, metadata FROM {} WHERE status IS NULL OR status != 'merged' ORDER BY id DESC LIMIT $1 OFFSET $2",
         id_table
     );