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_internet_cables.py

@@ -14,12 +14,14 @@ import json
 import os
 import re
 from decimal import Decimal
+from pathlib import Path
 
 import psycopg2
 from psycopg2.extras import Json, execute_values
 
 
-DATA_DIR = "internet_cables"
+PROJECT_ROOT = Path(__file__).parent.parent
+DATA_DIR = str(PROJECT_ROOT / "internet_cables")
 DB_NAME = "data_centers"
 
 CABLES_TABLE = "public.internet_cables"