已知各项均为正数的等比数列\(\{a_{n}\}\)的前\(n\)项和为\(S_{n}\)，若\(S_{3}=39\)，且\(3a_{3}\)是\(a_{5}\)与\(-a_{4}\)的等差中项．
\((1)\)求数列\(\{a_{n}\}\)的通项公式；
\((2)\)若数列\(\{b_{n}\}\)的前\(n\)项和为\(T_{n}\)，且\(b_{n}=4\log_{3}a_{n}\)，求\(\dfrac{1}{T_{1}}+\dfrac{1}{T_{2}}+\dfrac{1}{T_{3}}+⋯+\dfrac{1}{T_{n}}.\)