Fix path references in scripts after reorganization

Update 8 scripts to use Path(__file__).parent.parent as PROJECT_ROOT
so they resolve data/, output/, and internet_cables/ relative to the
project root rather than the caller's working directory.

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

scripts/load_postgis_data_centers.py

@@ -3,13 +3,15 @@ import argparse
 import csv
 import os
 from decimal import Decimal
+from pathlib import Path
 
 import psycopg2
 from psycopg2.extras import execute_values
 
 
-CSV_PATH = "US_DC_Sample_geocoded.csv"
-IM3_CSV_PATH = "new/IM3_Existing_DataCenters.csv"
+PROJECT_ROOT = Path(__file__).parent.parent
+CSV_PATH = str(PROJECT_ROOT / "data" / "US_DC_Sample_geocoded.csv")
+IM3_CSV_PATH = str(PROJECT_ROOT / "new" / "IM3_Existing_DataCenters.csv")
 TABLE = "public.us_dc_sample_geocoded"
 DB_NAME = "data_centers"