feat: unify TKG face_track external_id to trace_N, add trace restore endpoint

- tkg.rs: use trace_N as primary external_id, delete duplicate face_track_N nodes
- trace_agent_api.rs: add POST /trace/:id/restore to undo soft delete
- ensure 1:1 mapping: each trace has exactly one TKG node with full profile

src/api/trace_agent_api.rs

@@ -57,6 +57,10 @@ pub fn trace_agent_routes() -> Router<crate::api::types::AppState> {
             "/api/v1/file/:file_uuid/trace/:trace_id",
             delete(delete_trace),
         )
+        .route(
+            "/api/v1/file/:file_uuid/trace/:trace_id/restore",
+            post(restore_trace),
+        )
         .route(
             "/api/v1/file/:file_uuid/trace/:trace_id/merge/:target_trace_id",
             post(merge_trace),
@@ -1898,3 +1902,79 @@ async fn merge_trace(
         "tkg_nodes_deleted": tkg_deleted
     }))
 }
+
+async fn restore_trace(
+    State(state): State<crate::api::types::AppState>,
+    Path((file_uuid, trace_id)): Path<(String, i32)>,
+) -> Json<serde_json::Value> {
+    let qdrant = crate::core::db::qdrant_db::QdrantDb::new();
+
+    // Restore Qdrant points: clear deleted status
+    let filter = serde_json::json!({
+        "must": [
+            {"key": "file_uuid", "match": {"value": file_uuid}},
+            {"key": "trace_id", "match": {"value": trace_id}},
+            {"key": "status", "match": {"value": "deleted"}}
+        ]
+    });
+
+    // Get count of points to restore
+    let points_to_restore = qdrant.scroll_all_points("_faces", filter.clone(), 1).await
+        .map(|pts| pts.len()).unwrap_or(0);
+
+    if points_to_restore == 0 {
+        return Json(serde_json::json!({
+            "success": false,
+            "error": "Trace not found or not deleted"
+        }));
+    }
+
+    // Clear the deleted status
+    let clear_payload = serde_json::json!({
+        "status": serde_json::Value::Null
+    });
+
+    let qdrant_restored = match qdrant.update_payload_by_filter("_faces", filter, clear_payload).await {
+        Ok(_) => {
+            tracing::info!("[restore_trace] Restored {} Qdrant points for trace {} in {}", points_to_restore, trace_id, file_uuid);
+            true
+        }
+        Err(e) => {
+            tracing::error!("[restore_trace] Failed to restore Qdrant points: {}", e);
+            return Json(serde_json::json!({
+                "success": false,
+                "error": format!("Failed to restore Qdrant points: {}", e)
+            }));
+        }
+    };
+
+    // Restore TKG node: clear deleted status
+    let nodes_table = crate::core::db::schema::table_name("tkg_nodes");
+    let ext_id_trace = format!("trace_{}", trace_id);
+
+    let tkg_result = sqlx::query(&format!(
+        "UPDATE {} SET properties = properties - 'status' \
+         WHERE file_uuid = $1 AND node_type = 'face_track' AND external_id = $2",
+        nodes_table
+    ))
+    .bind(&file_uuid)
+    .bind(&ext_id_trace)
+    .execute(state.db.pool())
+    .await;
+
+    let tkg_restored = match tkg_result {
+        Ok(r) => r.rows_affected(),
+        Err(e) => {
+            tracing::error!("[restore_trace] Failed to restore TKG node: {}", e);
+            0
+        }
+    };
+
+    Json(serde_json::json!({
+        "success": true,
+        "file_uuid": file_uuid,
+        "trace_id": trace_id,
+        "qdrant_restored": qdrant_restored,
+        "tkg_nodes_restored": tkg_restored
+    }))
+}

src/core/processor/tkg.rs

@@ -1153,7 +1153,8 @@ async fn build_face_track_nodes_from_qdrant(
 
     let mut count = 0;
     for (tid, agg) in &traces {
-        let external_id = format!("face_track_{}", tid);
+        // Use trace_N as primary external_id (consistent with cluster_agent)
+        let external_id = format!("trace_{}", tid);
         let label = format!("Face Trace {}", tid);
 
         // Compute average pose for this trace
@@ -1217,6 +1218,17 @@ async fn build_face_track_nodes_from_qdrant(
         .execute(pool)
         .await?;
 
+        // Delete old face_track_N format to avoid duplicates
+        let old_external_id = format!("face_track_{}", tid);
+        let _ = sqlx::query(&format!(
+            "DELETE FROM {} WHERE file_uuid = $1 AND node_type = 'face_track' AND external_id = $2",
+            nodes_table
+        ))
+        .bind(file_uuid)
+        .bind(&old_external_id)
+        .execute(pool)
+        .await;
+
         count += 1;
     }