feat: resolve trial-only playback via trialDuration/effectiveDuration

VIP songs for non-VIP accounts return a ~30s trial fragment. The player used the full duration for isNearEnd, so the trial end didn't trigger auto-advance (~60s stall), and currentSong.duration stayed full, leaving the UI progress stuck.

- provider.ts: SongUrlResult {url, trialDuration?}; getSongUrl signature
- netease.ts: parseNeteaseTrial (freeTrialInfo start/end in seconds) + getSongUrl
- qq.ts: parseQqTrial (isTryout/tryEnd) + getSongUrl
- bilibili/youtube: getSongUrl returns {url}
- instance.ts: resolveAndPlay uses effectiveDuration = trialDuration ?? duration -> nearEnd at trial end -> native auto-advance; BotStatus.effectiveDuration
- VIP account: freeTrialInfo absent -> full duration -> full playback (no toggle)

Backward compatible (optional fields; getSongUrl has a single caller, updated).
Tests: parseTrial assertions (seconds/alias/ms-fallback). 14 pass.

src/music/qq.test.ts

@@ -1,5 +1,5 @@
 import { describe, it, expect } from "vitest";
-import { mapQqAlbums, mapQqSongs } from "./qq.js";
+import { mapQqAlbums, mapQqSongs, parseQqTrial } from "./qq.js";
 
 describe("QQ adapter", () => {
   it("mapQqSongs maps QQMusicApi-style song entries", () => {
@@ -40,6 +40,19 @@ describe("QQ adapter", () => {
     expect(out[3].vip).toBe(false);
   });
 
+  it("parseQqTrial maps isTryout/tryout to trial seconds", () => {
+    // 非试听（VIP/免费）
+    expect(parseQqTrial({ isTryout: 0 })).toBeUndefined();
+    expect(parseQqTrial({})).toBeUndefined();
+    // 试听（秒）
+    expect(parseQqTrial({ isTryout: 1, tryBegin: 0, tryEnd: 30 })).toBe(30);
+    expect(parseQqTrial({ tryout: true, begin: 0, end: 45 })).toBe(45);
+    // 毫秒兜底
+    expect(parseQqTrial({ isTryout: 1, tryBegin: 0, tryEnd: 30000 })).toBe(30);
+    // 异常
+    expect(parseQqTrial({ isTryout: 1, tryEnd: 0 })).toBeUndefined();
+  });
+
   it("mapQqAlbums maps albumMID-style raw entries", () => {
     const raw = [
       {