fix(terrain): reject out-of-range points at the proxy boundary

Rebased onto current main with review follow-ups folded in.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>

src/data/terrainHeightsProxy.js

@@ -35,7 +35,13 @@ export function parseTerrainPoints(raw) {
     if (parts.length !== 2) return null;
     const lon = Number(parts[0]);
     const lat = Number(parts[1]);
-    if (!Number.isFinite(lon) || !Number.isFinite(lat)) return null;
+    if (
+      !Number.isFinite(lon) ||
+      !Number.isFinite(lat) ||
+      Math.abs(lon) > 180 ||
+      Math.abs(lat) > 90
+    )
+      return null;
     points.push([lon, lat]);
   }
   return points;

src/data/terrainHeightsProxy.test.mjs

@@ -3,6 +3,7 @@
 import { test } from 'node:test';
 import assert from 'node:assert/strict';
 import {
+  parseTerrainPoints,
   fetchTerrainChunkWithRetry,
   resolveTerrainHeightRequest,
   terrainPointKey,
@@ -227,3 +228,13 @@ test('malformed height objects remain refresh failures, not absent readings', as
     assert.equal(response.cacheChanged, false);
   }
 });
+
+test('terrain parser rejects out-of-range WGS84 points and accepts inclusive bounds', () => {
+  for (const value of ['181,0', '-181,0', '0,91', '0,-91', '1,2;0,91'])
+    assert.equal(parseTerrainPoints(value), null, value);
+  assert.deepEqual(parseTerrainPoints('-180,-90;180,90;0,0'), [
+    [-180, -90],
+    [180, 90],
+    [0, 0],
+  ]);
+});