feat(anki): add media timing review before card creation

- Add draggable timing previews with audio playback and exact media ranges
- Support cancellation choices, including deleting existing cards

src/core/services/media-timing-preview.test.ts

@@ -0,0 +1,144 @@
+import assert from 'node:assert/strict';
+import { EventEmitter } from 'node:events';
+import net from 'node:net';
+import { describe, test } from 'node:test';
+import { buildMediaTimingPreviewArgs, MediaTimingPreviewSession } from './media-timing-preview';
+
+describe('buildMediaTimingPreviewArgs', () => {
+  test('creates a hidden audio-only reusable mpv session', () => {
+    const args = buildMediaTimingPreviewArgs('/tmp/review.sock', {
+      mediaPath: '/video/show.mkv',
+      audioTrackId: 3,
+      volume: 55,
+    });
+
+    assert.ok(args.includes('--no-video'));
+    assert.ok(args.includes('--force-window=no'));
+    assert.ok(args.includes('--idle=yes'));
+    assert.ok(args.includes('--pause=yes'));
+    assert.ok(args.includes('--input-ipc-server=/tmp/review.sock'));
+    assert.ok(args.includes('--aid=3'));
+    assert.ok(args.includes('--volume=55'));
+    assert.equal(args.at(-2), '--');
+    assert.equal(args.at(-1), '/video/show.mkv');
+  });
+});
+
+test('preview session handles socket errors after connecting', async () => {
+  const socket = new net.Socket();
+  const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
+  child.kill = () => true;
+  const session = new MediaTimingPreviewSession({
+    platform: 'linux',
+    spawnProcess: () => child as never,
+    connectSocket: () => {
+      queueMicrotask(() => socket.emit('connect'));
+      return socket;
+    },
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+
+  await session.start({ mediaPath: '/video/show.mkv' });
+  assert.doesNotThrow(() => socket.emit('error', new Error('pipe closed')));
+  await assert.rejects(session.play(1, 2), /not ready/);
+  session.dispose();
+});
+
+test('preview session rejects a connection that finishes after disposal', async () => {
+  const socket = new net.Socket();
+  const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
+  child.kill = () => true;
+  const session = new MediaTimingPreviewSession({
+    platform: 'linux',
+    spawnProcess: () => child as never,
+    connectSocket: () => socket,
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+
+  const pendingStart = session.start({ mediaPath: '-playlist' });
+  session.dispose();
+  socket.emit('connect');
+
+  await assert.rejects(pendingStart, /closed/);
+  assert.equal(socket.destroyed, true);
+});
+
+test('preview session shares one startup across concurrent start calls', async () => {
+  const socket = new net.Socket();
+  const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
+  child.kill = () => true;
+  let spawnCount = 0;
+  const session = new MediaTimingPreviewSession({
+    platform: 'linux',
+    spawnProcess: () => {
+      spawnCount += 1;
+      return child as never;
+    },
+    connectSocket: () => socket,
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+
+  const firstStart = session.start({ mediaPath: '/video/show.mkv' });
+  const secondStart = session.start({ mediaPath: '/video/show.mkv' });
+  socket.emit('connect');
+
+  await Promise.all([firstStart, secondStart]);
+  assert.equal(spawnCount, 1);
+  session.dispose();
+});
+
+test('preview session can start again after a startup failure', async () => {
+  const socket = new net.Socket();
+  const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
+  child.kill = () => true;
+  let spawnCount = 0;
+  const session = new MediaTimingPreviewSession({
+    platform: 'linux',
+    spawnProcess: () => {
+      spawnCount += 1;
+      if (spawnCount === 1) throw new Error('spawn failed');
+      return child as never;
+    },
+    connectSocket: () => {
+      queueMicrotask(() => socket.emit('connect'));
+      return socket;
+    },
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+
+  await assert.rejects(session.start({ mediaPath: '/video/show.mkv' }), /spawn failed/);
+  await session.start({ mediaPath: '/video/show.mkv' });
+  assert.equal(spawnCount, 2);
+  session.dispose();
+});
+
+test('preview session bounds a connection attempt that never settles', async () => {
+  const child = new EventEmitter() as EventEmitter & { kill: () => boolean };
+  child.kill = () => true;
+  let nowMs = 0;
+  let connectAttempts = 0;
+  const session = new MediaTimingPreviewSession({
+    platform: 'linux',
+    spawnProcess: () => child as never,
+    connectSocket: () => {
+      connectAttempts += 1;
+      return new net.Socket();
+    },
+    now: () => {
+      const current = nowMs;
+      nowMs += 1_000;
+      return current;
+    },
+    schedule: (callback) => setTimeout(callback, 0),
+    cancelSchedule: (timeout) => clearTimeout(timeout),
+    removeSocketFile: () => undefined,
+    createSocketPath: () => '/tmp/review.sock',
+  });
+
+  await assert.rejects(session.start({ mediaPath: '/video/show.mkv' }), /Timed out starting/);
+  assert.equal(connectAttempts, 1);
+});