fix(embed): implement robust EmbedPlayerModal and guard resetTorrentStats

- Add `js/ui/components/EmbedPlayerModal.js` to implement the `VideoModal` interface for embed contexts (including `resetStats`).
- Update `js/ui/ModalManager.js` to detect embed mode and use `EmbedPlayerModal`.
- Clean up `js/embed.js` to remove local modal definition and add `postMessage` diagnostic logging.
- Update `js/app.js` `resetTorrentStats` log message and verify guard.
- Add unit tests for `EmbedPlayerModal` and `resetTorrentStats` logic.
- Add E2E reproduction script `tests/e2e/repro_issue.spec.ts`.

tests/unit/app_guard_logic.test.mjs

@@ -0,0 +1,51 @@
+import { test } from 'node:test';
+import assert from 'node:assert';
+
+/**
+ * Validates the logic used in Application.resetTorrentStats.
+ * Note: We test the function logic in isolation because importing the full Application class
+ * triggers side effects (network, webtorrent) that are difficult to mock in this unit test environment.
+ */
+function resetTorrentStats(context, logger) {
+    // Exact logic from js/app.js
+    if (context.videoModal) {
+      if (typeof context.videoModal.resetStats === "function") {
+        context.videoModal.resetStats();
+      } else {
+        logger.info(
+          "[Application] resetTorrentStats: videoModal.resetStats not available — skipping."
+        );
+      }
+    }
+}
+
+test('Application.resetTorrentStats logic', async (t) => {
+    const logger = {
+        info: () => {},
+        warn: () => {}
+    };
+
+    await t.test('does not throw when videoModal is null', () => {
+        const context = { videoModal: null };
+        assert.doesNotThrow(() => resetTorrentStats(context, logger));
+    });
+
+    await t.test('does not throw when videoModal is undefined', () => {
+        const context = { videoModal: undefined };
+        assert.doesNotThrow(() => resetTorrentStats(context, logger));
+    });
+
+    await t.test('does not throw when videoModal lacks resetStats', () => {
+        const context = { videoModal: { other: 1 } };
+        assert.doesNotThrow(() => resetTorrentStats(context, logger));
+    });
+
+    await t.test('calls resetStats when available', () => {
+        let called = false;
+        const context = {
+            videoModal: { resetStats: () => { called = true; } }
+        };
+        resetTorrentStats(context, logger);
+        assert.strictEqual(called, true);
+    });
+});

tests/unit/embed_player_modal.test.mjs

@@ -0,0 +1,34 @@
+import { test } from 'node:test';
+import assert from 'node:assert';
+import { EmbedPlayerModal } from '../../js/ui/components/EmbedPlayerModal.js';
+
+// Polyfill EventTarget for Node < 16 if needed, but likely available
+if (typeof EventTarget === 'undefined') {
+    global.EventTarget = class EventTarget {
+        constructor() { this.listeners = {}; }
+        addEventListener() {}
+        removeEventListener() {}
+        dispatchEvent() { return true; }
+    };
+}
+
+test('EmbedPlayerModal interface', async (t) => {
+    const modal = new EmbedPlayerModal();
+
+    await t.test('has expected methods', () => {
+        assert.strictEqual(typeof modal.load, 'function');
+        assert.strictEqual(typeof modal.getRoot, 'function');
+        assert.strictEqual(typeof modal.getVideoElement, 'function');
+        assert.strictEqual(typeof modal.setVideoElement, 'function');
+        assert.strictEqual(typeof modal.resetStats, 'function');
+        assert.strictEqual(typeof modal.updateStatus, 'function');
+        assert.strictEqual(typeof modal.setTorrentStatsVisibility, 'function');
+        assert.strictEqual(typeof modal.addEventListener, 'function');
+        assert.strictEqual(typeof modal.removeEventListener, 'function');
+        assert.strictEqual(typeof modal.dispatch, 'function');
+    });
+
+    await t.test('resetStats is no-op and does not throw', () => {
+        assert.doesNotThrow(() => modal.resetStats());
+    });
+});