Would the wife be sinful if she sought divorce before consummation because she discovered that the husband does not pray and does not go to the mosque for Friday prayers?

There is no sin in seeking a divorce if the avenues of advice have failed. The saying "work is worship" has its regulations. The husband is advised to adhere to the rulings of Friday prayer, for Allah commanded seeking His remembrance and abandoning trade at the time of the call, and after the prayer He permitted dispersing throughout the land and seeking sustenance, while increasing in the remembrance of Allah.