feat: add a submarine cable tool

Add find_submarine_cables over the bundled TeleGeography data: cables
passing through or landing in an area, or matching a name, with landing
points and the dataset's attribution. The local MCP server's fetch reads
the bundled data files a browser would load by URL, and nothing outside
that directory.

src/tools/index.js

@@ -10,6 +10,7 @@ import {
   getAircraftTrack,
 } from './queries/aviation.js';
 import { getWeatherMap, getWind } from './queries/atmosphere.js';
+import { findSubmarineCables } from './queries/cables.js';
 import { getHudCaption, situationBrief } from './queries/brief.js';
 import {
   findMilitaryInstallations,
@@ -93,6 +94,7 @@ export const coreTools = Object.freeze([
   getWeatherMap,
   getWind,
   getRecentImagery,
+  findSubmarineCables,
   getRegionalBrief,
   getCyclones,
   getFirePerimeters,