What is the Talmudic source for Ḥanukah?
In discussing candles for Shabbath, the Talmud (Shab. 21b) goes into a discussion about candles generally, touching upon Ḥanukah candles, and ultimately asks, "Mai Ḥanukah?" - "What is Ḥanukah?" - and from there goes into a brief discussion of the origins of the holiday. In Hebrew schools and Yeshivoth it is frequently taught, simplistically, that this is the "source" in the Gemara for Ḥanukah and that the Mishnah makes no mention of it (for reasons outside the scope of this question). But that's actually not true. This discussion in Shabbath draws from other places in the Talmud that discuss the holiday and its ritual lighting, most significantly pointing to the law in the last Mishnah in B"K, ch. 6, discussed in Bava Kama 62b, that one is not financially culpable if a damaging fire is ignited (G-d forbid) from one's Ḥanukah candles that were placed outside. If one were to look at the volumes of the Talmud and try to determine which came first - or, more precisely, which draws upon which, one would have to conclude that the B"K mention is the source, as the Mishnah predates the Gemara in Shab. But is the Mishnah the source for the Gemara, or is there another source that is not mentioned? I know that Megillath Ta'anith mentions Ḥanukah. Could that be considered the source?