Restore 0.2 m/s minimum speed (planner trained range), 2s ramp

Planner NN was trained with SLOW_WALK range [0.2, 0.8] m/s per NVIDIA
docs. Sending 0.0 m/s is out-of-distribution. Restored 0.2 minimum,
ramp now 0.2->0.8 over ~2s at 100Hz input loop.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gear_sonic_deploy/src/g1/g1_deploy_onnx_ref/include/input_interface/gamepad_manager.hpp

@@ -693,7 +693,7 @@ class GamepadManager : public InputInterface {
         double final_speed = planner_use_movement_speed_;
         double final_height = planner_use_height_;
 
-        // LOCKED TO SLOW_WALK for testing — speed 0.0-0.8 m/s
+        // LOCKED TO SLOW_WALK for testing — speed 0.2-0.8 m/s (planner trained range)
         // Proportional to stick magnitude with acceleration rate limiting.
         if (planner_stick_magnitude_ < dead_zone_) {
           // Stick in dead zone — IDLE
@@ -701,25 +701,25 @@ class GamepadManager : public InputInterface {
           final_movement = {0.0f, 0.0f, 0.0f};
           final_speed = -1.0f;
           final_height = -1.0f;
-          smoothed_speed_ = 0.0;  // Reset ramp when idle
+          smoothed_speed_ = 0.2;  // Reset to planner minimum so ramp starts there
         } else if (planner_use_movement_mode_ == static_cast<int>(LocomotionMode::CRAWLING) ||
                    planner_use_movement_mode_ == static_cast<int>(LocomotionMode::IDEL_KNEEL_TWO_LEGS)) {
           // Keep crawl/kneel modes as-is
           double normalized = std::min((planner_stick_magnitude_ - dead_zone_) / (1.0 - dead_zone_), 1.0);
           final_speed = 0.3 + normalized * (1.2 - 0.3);
         } else {
-          // Everything else → SLOW_WALK, 0.0-0.8 m/s
+          // Everything else → SLOW_WALK, 0.2-0.8 m/s (planner trained range)
           double normalized = std::min((planner_stick_magnitude_ - dead_zone_) / (1.0 - dead_zone_), 1.0);
-          double target_speed = normalized * 0.8;  // 0.0 at dead zone edge, 0.8 at full stick
+          double target_speed = 0.2 + normalized * (0.8 - 0.2);  // 0.2 min, 0.8 max
           // Rate-limit acceleration only (decel is instant)
-          constexpr double max_accel_per_frame = 0.002;  // 4s ramp 0→0.8 (100Hz input loop)
+          constexpr double max_accel_per_frame = 0.003;  // ~2s ramp 0.2→0.8 at 100Hz
           if (target_speed > smoothed_speed_) {
             smoothed_speed_ = std::min(target_speed, smoothed_speed_ + max_accel_per_frame);
           } else {
             smoothed_speed_ = target_speed;  // Instant decel
           }
           final_mode = static_cast<int>(LocomotionMode::SLOW_WALK);
-          final_speed = smoothed_speed_;
+          final_speed = std::max(smoothed_speed_, 0.2);  // Never below planner minimum
         }
 
         // Emergency stop resets to idle