feat(rail): add a Rail layer with keyless live trains

Live trains from 30 keyless operator feeds: GPS positions from 29 and
Irish Rail's station reports, shown as the operators publish them. 28
work out of the box; Renfe long and medium distance and KTMB appear once
their pack is built, because their vehicles name no route.

Packs are opt-in (scripts/build-rail-paths.mjs): the operator's own
route lines, stop names, next stops and trip-update delays for live
trains. Nothing downloads when the app starts, no train is placed from a
timetable, and no request carries a deployer's key.

src/data/railFeedsAsia.test.mjs

@@ -0,0 +1,63 @@
+// Asian feeds: Japan's live tram feeds (Manyōsen and Toyama), registered,
+// switched on with their licence basis recorded, and sorted into
+// categories.
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import {
+  RAIL_ENABLED_FEEDS,
+  classifyTrain,
+  getRailFeed,
+  getRegisteredRailFeed,
+  railFeedPositions,
+  railFeedsInRange,
+} from './railFeeds.js';
+
+const LIVE = ['jp-manyosen', 'jp-toyama-tram'];
+
+const feed = (id) => getRegisteredRailFeed(id);
+const kind = (id, routeId) => classifyTrain(feed(id), routeId);
+
+const TRAM = { category: 'transit', mode: 'tram' };
+
+test('the Japanese feeds are on, with their licence basis recorded', () => {
+  for (const id of LIVE) {
+    assert.ok(getRailFeed(id), `${id} is pollable`);
+    assert.ok(RAIL_ENABLED_FEEDS.includes(feed(id)), id);
+    assert.ok(feed(id).license, id);
+    assert.match(feed(id).licenseUrl, /^https:\/\//, id);
+    assert.ok(feed(id).attribution, id);
+    assert.ok(feed(id).terms.quote, `${id} quotes its terms`);
+    assert.match(feed(id).terms.note, /read 2026-11-10/, id);
+    assert.doesNotMatch(feed(id).terms.note, /@/, id);
+    assert.equal(railFeedPositions(feed(id)), 'gps', id);
+    assert.match(feed(id).url, /^https:\/\/gtfs-rt-files\.buscatch\.jp\//);
+  }
+  assert.equal(
+    feed('jp-toyama-tram').staticGtfsUrl,
+    undefined,
+    'its static GTFS codes the tram as buses',
+  );
+});
+
+test('Japan: the Manyōsen and Toyama trams are transit', () => {
+  assert.deepEqual(kind('jp-manyosen', '1'), TRAM);
+  assert.deepEqual(
+    kind('jp-toyama-tram', '富山港線（南富山）(3004-1)'),
+    TRAM,
+    'a route id seen live',
+  );
+});
+
+test('each Japanese tram feed is polled around its own city only', () => {
+  const near = (lat, lon) => railFeedsInRange(lat, lon).map((f) => f.id);
+  // Takaoka for the Manyōsen, Toyama station for the city tram.
+  assert.ok(near(36.75, 137.02).includes('jp-manyosen'));
+  assert.ok(near(36.7, 137.21).includes('jp-toyama-tram'));
+  // Tokyo and Nagoya are hundreds of kilometres off.
+  for (const [lat, lon] of [
+    [35.68, 139.77],
+    [35.17, 136.88],
+  ])
+    for (const id of LIVE) assert.ok(!near(lat, lon).includes(id), id);
+  for (const id of LIVE) assert.ok(feed(id).loadRadiusKm <= 25, id);
+});