Move metadata xlsx/TSV to /mnt/data/projects/cupido/

Consolidates everything bulky (tracking DBs, targets, metadata
spreadsheet) under a single DATA_VOLUME root outside the ownCloud-synced
repo. Notebooks now use a visible DATA_DIR = Path(...) idiom rather than
walking up the filesystem with PROJECT_ROOT.parent — easier for students
with no Python background to follow.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

scripts/load_roi_data.py

@@ -13,7 +13,7 @@ from pathlib import Path
 
 import pandas as pd
 
-from config import VIDEO_INFO_XLSX
+from config import VIDEO_INFO_TSV
 
 
 # Metadata columns to copy onto every tracking sample. These are the xlsx
@@ -68,7 +68,7 @@ def load_roi_data(meta: pd.DataFrame | None = None) -> pd.DataFrame:
         sample. Empty if nothing could be loaded.
     """
     if meta is None:
-        meta = pd.read_csv(VIDEO_INFO_XLSX.with_suffix(".tsv"), sep="\t")
+        meta = pd.read_csv(VIDEO_INFO_TSV, sep="\t")
 
     db_cache: dict = {}
     chunks: list[pd.DataFrame] = []