What is the tajweed ruling for "لِرَبِّكَ" in Surat Al-Kawthar?

Among the tajwid rulings related to the noble verse is the tafkheem (emphasis) of the letter ra in the Almighty’s saying: (لربك - li Rabbika). The reciters have agreed upon its tafkheem, and even Warsh concurred with the majority here because the kasra (i-vowel) on the lam preceding the ra is not in the same word. Thus, it is considered as if it were separate, in accordance with Al-Shatibi’s saying in Hirz al-Amani: "And what comes after an accidental kasra or a separate [letter] / Then emphasize it, for this is its well-established ruling."