feat: add play-dl search resolver

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

tests/media/playDlResolver.test.ts

@@ -0,0 +1,49 @@
+import { describe, expect, it, vi } from "vitest";
+import { createPlayDlResolver } from "../../src/media/playDlResolver";
+
+describe("createPlayDlResolver", () => {
+  it("returns the first YouTube search result", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(async () => [
+        { title: "Song Result", url: "https://youtube.com/watch?v=abc" },
+      ]),
+      spotify: vi.fn(),
+    });
+
+    await expect(resolver.searchYouTube("artist song")).resolves.toEqual({
+      title: "Song Result",
+      url: "https://youtube.com/watch?v=abc",
+    });
+  });
+
+  it("turns Spotify track metadata into a YouTube search query", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(async () => [
+        { title: "Artist - Track", url: "https://youtube.com/watch?v=track" },
+      ]),
+      spotify: vi.fn(async () => ({
+        type: "track",
+        name: "Track",
+        artists: [{ name: "Artist" }],
+      })),
+    });
+
+    await expect(
+      resolver.resolveSpotifyTrack("https://open.spotify.com/track/123"),
+    ).resolves.toEqual({
+      title: "Artist - Track",
+      url: "https://youtube.com/watch?v=track",
+    });
+  });
+
+  it("rejects Spotify playlists in this phase", async () => {
+    const resolver = createPlayDlResolver({
+      search: vi.fn(),
+      spotify: vi.fn(async () => ({ type: "playlist", name: "Playlist" })),
+    });
+
+    await expect(
+      resolver.resolveSpotifyTrack("https://open.spotify.com/playlist/123"),
+    ).rejects.toThrow("Only Spotify track URLs are supported");
+  });
+});