stop method

    async stop() {
      if (state !== "recording" || !recorder || !stream) {
        return new Blob([], { type: "video/webm" });
      }

      state = "stopping";

      return new Promise<Blob>((resolve) => {
        recorder!.onstop = () => {
          const blob = new Blob(chunks, {
            type: recorder!.mimeType || "video/webm",
          });
          log.info(`Recording stopped — ${(blob.size / 1024).toFixed(1)} KB`);

          // Release tracks
          stream!.getTracks().forEach((t) => t.stop());
          stream = null;
          recorder = null;
          chunks = [];
          state = "inactive";

          resolve(blob);
        };

        recorder!.stop();
      });
    },