Learn Swedish: Ge mig ett rakt svar. - Give me a straight answer.

Yes, exactly. Just like in English, ett rakt svar means a direct, honest, or straightforward answer. You can also describe a person's communication style as being rak (direct or straightforward).

This lesson is about stylistic fronting of adjectives. Why isn't rakt fronted here for emphasis?

Stylistic fronting applies to predicative adjectives, which are adjectives that describe the subject via a verb like 'to be' (for example, if the sentence were 'Svaret var rakt'). In this sentence, rakt is an attributive adjective, meaning it is attached directly to the noun it modifies within the object phrase (ett rakt svar). You cannot split an attributive adjective from its noun to front it.

Could I say Ge ett rakt svar till mig instead?

Grammatically, yes, you can use till (to) when you put the recipient last. However, Ge mig ett rakt svar is the much more natural and common phrasing. Swedish strongly prefers the double-object construction where the indirect object (mig) goes directly after the verb, especially when it is a short pronoun.

Just as a quick refresher, why is it rakt and not rak here?

Svar is a neuter noun (ett svar). Because the adjective is modifying an ett-word, it must take the neuter agreement suffix -t, making it rakt.