Is it obligatory to repeat the ritual bath (ghusl) if I performed it after the cessation of menstruation, while there were dark-tinged discharges that I did not notice, and is performing the ghusl after the cessation of these discharges with the sole intention of janabah (major ritual impurity) sufficient for both janabah and menstruation?

If a woman sees purity by one of its two signs (dryness or white discharge) and then performs ghusl, her ghusl is valid. Any subsequent discharge is not considered menstruation. However, if she performs ghusl while still having discharge before verifying purity, her ghusl is insufficient for the post-menstrual ghusl, and she must repeat the ghusl after confirming purity. It is more cautious to repeat the post-menstrual ghusl once more.