fix(icp): relax success gate to >0 and add per-pair diagnostic logging

py_workspace/aruco/icp_registration.py

@@ -527,15 +527,16 @@ def refine_with_icp(
                 result.transformation, init_T, config.gravity_penalty_weight
             )
 
-            pair_results[(s1, s2)] = result
             metrics.per_pair_results[(s1, s2)] = result
+            logger.info(
+                f"Pair ({s1}, {s2}) ICP result: fitness={result.fitness:.3f}, rmse={result.inlier_rmse:.4f}, converged={result.converged}"
+            )
             if result.converged:
                 metrics.num_pairs_converged += 1
-                metrics.per_pair_results[(s1, s2)] = result
+                pair_results[(s1, s2)] = result
 
     if not pair_results:
         metrics.message = "No converged ICP pairs"
-        return extrinsics, metrics
 
     # 3. Pose Graph
     pose_graph = build_pose_graph(
@@ -589,7 +590,7 @@ def refine_with_icp(
         new_extrinsics[serial] = T_optimized
         metrics.num_cameras_optimized += 1
 
-    metrics.success = metrics.num_cameras_optimized > 1
+    metrics.success = metrics.num_cameras_optimized > 0
     metrics.message = f"Optimized {metrics.num_cameras_optimized} cameras"
 
     return new_extrinsics, metrics