Add CSV plotting and episode recording functionality

- Implemented `plot_data_csv.py` to read CSV files and generate plots for velocity and linear acceleration signals.
- Created `record1.py` for recording ESP32 IMU data, DIN/DOUT states, and RealSense camera images into episodes.
- Enhanced `ProviderWorldIMUVelocityEstimator` to include stationary detection logic, resetting velocity when stationary.
- Updated `EpisodeWriter` to save episode data with timestamped filenames for better organization.

record_episode.py

@@ -277,6 +277,9 @@ class ProviderWorldIMUVelocityEstimator:
 
         self.v_world = np.zeros(3, dtype=float)
         self.last_acc_world_ms2 = np.zeros(3, dtype=float)
+        self.stationary_count = 0
+        self.stationary_count_required = 10
+        self.gyro_deadband = 3.0  # deg/s
 
     def reset(self):
         self.start_t_ms = None
@@ -288,6 +291,7 @@ class ProviderWorldIMUVelocityEstimator:
 
         self.v_world[:] = 0.0
         self.last_acc_world_ms2[:] = 0.0
+        self.stationary_count = 0
 
     def gravity_body_g(self, roll_deg, pitch_deg):
         roll = math.radians(roll_deg)
@@ -372,9 +376,20 @@ class ProviderWorldIMUVelocityEstimator:
 
         # ---------------- deadband before rotation ----------------
         # Norm is unchanged by pure rotation, so before/after rotation both okay.
-        if np.linalg.norm(linear_acc_body_ms2) < self.acc_deadband:
+        gyro_body_dps = np.array(packet["gyro_dps"], dtype=float)
+
+        acc_is_small = np.linalg.norm(linear_acc_body_ms2) < self.acc_deadband
+        gyro_is_small = np.linalg.norm(gyro_body_dps) < self.gyro_deadband
+
+        if acc_is_small and gyro_is_small:
+            self.stationary_count += 1
             linear_acc_body_ms2[:] = 0.0
 
+            if self.stationary_count >= self.stationary_count_required:
+                self.v_world[:] = 0.0
+        else:
+            self.stationary_count = 0
+
         # ---------------- body frame -> world frame ----------------
         R_bw = self.rot_body_to_world(
             roll_deg=roll_deg,
@@ -475,7 +490,9 @@ class EpisodeWriter:
         if self.recording:
             return
 
-        episode_name = "episode_" + datetime.now().strftime("%Y%m%d_%H%M%S")
+        episode_time = datetime.now().strftime("%Y%m%d_%H%M%S")
+        episode_name = f"episode_{episode_time}"
+
         self.episode_dir = self.root_dir / episode_name
 
         self.rgb_dir = self.episode_dir / "rgb"
@@ -489,7 +506,7 @@ class EpisodeWriter:
         if self.save_depth:
             self.depth_dir.mkdir(parents=True, exist_ok=True)
 
-        csv_path = self.episode_dir / "data.csv"
+        csv_path = self.episode_dir / f"episode_{episode_time}_data.csv"
         self.csv_file = open(csv_path, "w", newline="", encoding="utf-8")
 
         fieldnames = [