fix: zero-init TGS empty_trigrid_node_ + AOS Point/AOSNode (root-cause CI flakes)

cpp/travel/core/travel/aos.hpp

@@ -26,19 +26,25 @@ namespace travel {
 
     class AOSNode {
         public:
-            uint start;
-            uint end;
-            int label;
-
-            AOSNode() : label(-1) {} 
+            // start/end were declared without in-class initializers; combined
+            // with the uninit `int label` in `Point`, this leaked stack
+            // garbage into the per-channel node lists in horizontalUpdate
+            // and made cluster filtering decisions in labelPointcloud
+            // run-to-run nondeterministic. Zero-init makes the algorithm
+            // produce the same partition every time the input is the same.
+            uint start = 0;
+            uint end   = 0;
+            int  label;
+
+            AOSNode() : label(-1) {}
     };
 
     class Point {
         public:
-            float x,y,z;
-            uint idx;
+            float x{0.0f}, y{0.0f}, z{0.0f};
+            uint idx{0};
             bool valid = false;
-            int label;
+            int  label{0};
     };
 
     template <typename T>

cpp/travel/core/travel/tgs.hpp

@@ -358,13 +358,22 @@ namespace travel {
             empty_trigrid_node_.check_life = 10;
             empty_trigrid_node_.depth = -1;
 
-            empty_trigrid_node_.normal;
-            empty_trigrid_node_.mean_pt;
-            empty_trigrid_node_.d = 0;
-
-            empty_trigrid_node_.singular_values;
-            empty_trigrid_node_.eigen_vectors;
-            empty_trigrid_node_.weight = 0;
+            // The four lines below were no-op expression statements — almost
+            // certainly intended as zero-initializations but missing the
+            // assignment. Eigen types do not zero-init by default for
+            // performance, so without these the empty_trigrid_node_ ships
+            // four uninitialized members; copies of it then seed every
+            // node in trigrid_field_ with stack garbage. The algorithm
+            // overwrites these in the common path, but a few edge cases
+            // (small empty cells, boundary nodes) end up reading them,
+            // which surfaces as run-to-run nondeterminism downstream.
+            empty_trigrid_node_.normal          = Eigen::Vector3f::Zero();
+            empty_trigrid_node_.mean_pt         = Eigen::Vector3f::Zero();
+            empty_trigrid_node_.d               = 0;
+
+            empty_trigrid_node_.singular_values = Eigen::Vector3f::Zero();
+            empty_trigrid_node_.eigen_vectors   = Eigen::Matrix3f::Zero();
+            empty_trigrid_node_.weight          = 0;
 
             empty_trigrid_node_.th_dist_d = 0;
             empty_trigrid_node_.th_outlier_d = 0;