fix(webtorrent): ensure magnet webseeds are used in stream

Extracts `ws` (web seed) parameters from the magnet link and merges them with the explicit `urlList` (e.g., from direct URL) when initializing the WebTorrent stream. This fixes a regression where magnet-embedded web seeds were ignored if a direct URL was provided.

- Updates `js/magnets.js` to parse `ws` parameters and export `webSeedsFromMagnet`.
- Updates `js/webtorrent.js` to merge magnet web seeds with `opts.urlList`.
- Adds regression test `tests/webtorrent-webseeds.test.mjs`.

Co-authored-by: PR0M3TH3AN <[email protected]>

tests/webtorrent-webseeds.test.mjs

@@ -0,0 +1,76 @@
+
+import test from "node:test";
+import assert from "node:assert/strict";
+
+// Setup globals required by webtorrent.js
+if (typeof self === 'undefined') global.self = global;
+if (typeof navigator === 'undefined') {
+  global.navigator = {
+    userAgent: 'test',
+    serviceWorker: {
+      register: async () => ({ active: true }),
+      ready: Promise.resolve({ active: true }),
+      controller: { postMessage: () => {} },
+      addEventListener: () => {},
+      removeEventListener: () => {},
+    }
+  };
+}
+if (typeof window === 'undefined') {
+    global.window = {
+        location: { hostname: 'localhost', origin: 'http://localhost' },
+        isSecureContext: true,
+        navigator: global.navigator
+    }
+}
+if (typeof global.location === 'undefined') {
+    global.location = global.window.location;
+}
+
+// Import dynamic to ensure globals are set
+const { TorrentClient } = await import('../js/webtorrent.js');
+
+class MockWebTorrent {
+  constructor() {
+    this.torrents = [];
+  }
+  add(magnet, opts, cb) {
+    this.lastAdd = { magnet, opts };
+    const torrent = {
+        on: () => {},
+        files: [{name: 'video.mp4', streamTo: () => {}}],
+        once: () => {},
+        destroy: () => {},
+    };
+    if (cb) cb(torrent);
+    return torrent;
+  }
+  destroy() {}
+  createServer() {}
+}
+
+test("streamVideo merges magnet web seeds with explicit web seeds", async () => {
+  const client = new TorrentClient({ webTorrentClass: MockWebTorrent });
+  client.serviceWorkerDisabled = true;
+
+  const magnet = 'magnet:?xt=urn:btih:123&ws=http://magnet-seed.com/file.mp4';
+  const urlList = ['http://direct-url.com/video.mp4'];
+
+  const videoElement = {
+      play: async () => {},
+      addEventListener: () => {},
+      muted: false,
+      crossOrigin: null // streamVideo sets this
+  };
+
+  try {
+      await client.streamVideo(magnet, videoElement, { urlList });
+  } catch (e) {
+      console.log(e);
+  }
+
+  const lastAdd = client.client.lastAdd;
+
+  assert.ok(lastAdd.opts.urlList.includes('http://magnet-seed.com/file.mp4'), "Magnet web seed missing");
+  assert.ok(lastAdd.opts.urlList.includes('http://direct-url.com/video.mp4'), "Explicit web seed missing");
+});