Fix schema check and update import paths

- Use `collect_schema` for accurate column validation in Polars and
  correct
  relative import paths for statistical modules.

parser.py

@@ -77,7 +77,7 @@ def parse_csv(csv_path: PathLike) -> pl.LazyFrame:
     """
     lf = pl.scan_csv(csv_path, schema_overrides={"ID": pl.String, "Data": pl.String})
 
-    if "Timestamp" not in lf.columns:
+    if "Timestamp" not in lf.collect_schema().names():
         lf = lf.with_row_index("Timestamp")
 
     byte_exprs = []

stats/correlation.py

@@ -9,8 +9,8 @@ import numpy as np
 import pandas as pd
 import plotly.graph_objects as go
 
-from utils.extractor import load_data
-from utils.extractor import to_int
+from stats.utils.extractor import load_data
+from stats.utils.extractor import to_int
 
 def _format_can_id_vec(s: pd.Series) -> pd.Series:
     s = s.astype('string').str.strip()

stats/entropy.py

@@ -9,8 +9,8 @@ import numpy as np
 import pandas as pd
 import plotly.graph_objects as go
 
-from utils.extractor import load_data
-from utils.extractor import to_int
+from stats.utils.extractor import load_data
+from stats.utils.extractor import to_int
 
 def _format_can_id_vec(s: pd.Series) -> pd.Series:
     s = s.astype('string').str.strip()

stats/frequency.py

@@ -7,7 +7,7 @@ from pathlib import Path
 import numpy as np
 import pandas as pd
 import plotly.graph_objects as go
-from utils.extractor import load_data
+from stats.utils.extractor import load_data
 
 def _format_can_id_vec(s: pd.Series) -> pd.Series:
     s = s.astype('string').str.strip()

stats/id_viewer.py

@@ -7,7 +7,7 @@ from pathlib import Path
 import numpy as np
 import pandas as pd
 import plotly.graph_objects as go
-from utils.extractor import load_data
+from stats.utils.extractor import load_data
 
 def _format_can_id_vec(s: pd.Series) -> pd.Series:
     s = s.astype('string').str.strip()