feat(earth): cable state management, hover/lock visual separation, fix isSameCable undefined bug

frontend/public/earth/js/cables.js

@@ -2,7 +2,7 @@
 
 import * as THREE from 'three';
 
-import { CONFIG, CABLE_COLORS, PATHS } from './constants.js';
+import { CONFIG, CABLE_COLORS, PATHS, CABLE_STATE } from './constants.js';
 import { latLonToVector3 } from './utils.js';
 import { updateEarthStats, showStatusMessage } from './ui.js';
 import { showInfoCard } from './info-card.js';
@@ -340,3 +340,25 @@ export function getCablesById(cableId) {
 export function getLandingPoints() {
   return landingPoints;
 }
+
+const cableStates = new Map();
+
+export function getCableState(cableId) {
+  return cableStates.get(cableId) || CABLE_STATE.NORMAL;
+}
+
+export function setCableState(cableId, state) {
+  cableStates.set(cableId, state);
+}
+
+export function clearAllCableStates() {
+  cableStates.clear();
+}
+
+export function getCableStateInfo() {
+  const states = {};
+  cableStates.forEach((state, cableId) => {
+    states[cableId] = state;
+  });
+  return states;
+}