fix fetch reliability, memory leaks, and click-seek bug - #13

  private async fetchLyrics() {
    // Cancel any in-flight fetch to prevent stale results from racing
    this.fetchAbortController?.abort();
    const controller = new AbortController();
    this.fetchAbortController = controller;

    this.isLoading = true;
    this.lyrics = undefined;
    this.lyricsSource = null;
    this.availableSources = [];
    this.currentSourceIndex = 0;
    this.isFetchingAlternatives = false;
    this.hasFetchedAllProviders = false;
    try {
      const resolvedMetadata = await this.resolveSongMetadata();
      // If a newer fetch was triggered while we awaited, bail out
      if (controller.signal.aborted) return;

      const isMusicIdOnlyRequest =
        Boolean(this.musicId) &&
        !this.songTitle &&
        !this.songArtist &&
        !this.query;

      const collectedSources: { lines: LyricsLine[]; source: string }[] = [];

      if (resolvedMetadata?.metadata && !isMusicIdOnlyRequest) {
        const title = resolvedMetadata.metadata.title?.trim() || '';
        const artist = resolvedMetadata.metadata.artist?.trim() || '';

        const youLyResults = await AmLyrics.fetchLyricsFromYouLyPlus(
          title,
          artist,
          resolvedMetadata.metadata,
        );

        if (youLyResults && youLyResults.length > 0) {
          collectedSources.push(...youLyResults);
        }
      }

      if (collectedSources.length === 0 && resolvedMetadata?.metadata) {
        const tidalResult = await AmLyrics.fetchLyricsFromTidal(
          resolvedMetadata.metadata,
          resolvedMetadata.catalogIsrc,
        );
        if (tidalResult && tidalResult.lines.length > 0) {
          collectedSources.push({
            lines: tidalResult.lines,
            source: 'Tidal',
          });
        }
      }

      // Fallback: LRCLIB
      if (collectedSources.length === 0 && resolvedMetadata?.metadata) {
        const lrclibResult = await AmLyrics.fetchLyricsFromLrclib(
          resolvedMetadata.metadata,
        );
        if (lrclibResult && lrclibResult.lines.length > 0) {
          collectedSources.push({
            lines: lrclibResult.lines,
            source: 'LRCLIB',
          });
        }
      }

      if (collectedSources.length === 0 && resolvedMetadata?.metadata) {
        const geniusResult = await AmLyrics.fetchLyricsFromGenius(
          resolvedMetadata.metadata,
        );
        if (geniusResult && geniusResult.lines.length > 0) {
          collectedSources.push({
            lines: geniusResult.lines,
            source: 'Genius',
          });
        }
      }

      this.hasFetchedAllProviders =
        collectedSources.length === 0 ||
        collectedSources.some(
          s =>
            s.source === 'LRCLIB' ||
            s.source === 'Tidal' ||
            s.source === 'Genius',
        );

      if (collectedSources.length > 0) {
        this.availableSources = AmLyrics.mergeAndSortSources(collectedSources);

        this.currentSourceIndex = 0;
        this.lyrics = this.availableSources[0].lines;
        this.lyricsSource = this.availableSources[0].source;
        await this.onLyricsLoaded();
        return;