Fix coverage: add /api/coverage route, remove stray gather code from loadCoverage

scripts/check_positions.py

@@ -0,0 +1,22 @@
+import json
+
+data = json.load(open(r'F:\seismic_webapp\data\index.json'))
+
+nodes_with_data = [n for n in data['nodes'].values() if n.get('dates') and len(n['dates']) > 0]
+print(f'Nodes avec donnees: {len(nodes_with_data)}')
+
+print('\n--- Nodes avec donnees et leurs positions ---')
+for n in nodes_with_data[:10]:
+    pos = n.get('position')
+    has_pos = pos and pos.get('easting') and pos.get('northing')
+    print(f"Node {n['id']}: hasPos={has_pos}, pos={pos}")
+
+print('\n--- Nodes avec donnees SANS position valide ---')
+no_pos_count = 0
+for n in nodes_with_data:
+    pos = n.get('position')
+    if not pos or not pos.get('easting') or not pos.get('northing'):
+        print(f"Node {n['id']}: pos={pos}")
+        no_pos_count += 1
+        
+print(f'\nTotal nodes sans position valide: {no_pos_count}')