Is a ransom (fidyah) obligatory for me because I did not perform ihram from a miqat outside Makkah, given that I am a resident of Makkah and performed ihram from Al-Taneem?

If you arrive in Mecca from outside, intending to perform a ritual (Nusuk), it is obligatory to enter into a state of Ihram from the Miqat you pass through. It is not permissible to delay Ihram until Mecca. If you do so, you are liable for a dam (atonement sacrifice) which must be slaughtered in Mecca and distributed among its poor. Your ignorance of the ruling does not exempt you from the dam. However, if your return to Mecca is to visit your family, and you intend to perform Umrah after some time, some scholars have permitted not needing to enter Ihram from the Miqat, and thus no dam is required of you. This is the view held by Sheikh Al-Uthaymeen.