Round 2 fixes: rotated fence corners, pt2line before Hough, incremental correction, loc_rms, dynamic decay

include/car_nav_lite/fence_model.hpp

@@ -35,6 +35,9 @@ struct FenceModel {
     // Pre-computed wall positions for localization
     double left_x = -2.5, right_x = 2.5;
     double bottom_y = -2.5, top_y = 2.5;
+    // Pre-computed corner points for drawing rotated fence
+    double p_lb_x=0, p_lb_y=0, p_lt_x=0, p_lt_y=0;
+    double p_rb_x=0, p_rb_y=0, p_rt_x=0, p_rt_y=0;
     double yaw_field = 0.0;
     double width = 0.0, height = 0.0;
     double cx = 0.0, cy = 0.0;

include/car_nav_lite/grid_map.hpp

@@ -51,6 +51,7 @@ public:
     // ── Layered map (fence + cone + dynamic) ──
     void freezeSessionMap();
     void composeLayers();
+    void decayDynamic(uint8_t amount = 10);
 
     // ── Pre-built obstacle marks ───────────────────────
     void markCircle(double wx, double wy, double radius, uint8_t value = 255);