Learn Swedish: Väva gör hon varje dag, men hon har inte broderat på fem år. - Weaving she does every day, but she has not embroidered for five years.

This is the core of fronting an infinitive verb. When you move an infinitive like väva to the front of the sentence for emphasis, you still need a conjugated verb in the second position to follow the V2 (verb-second) rule. Swedish uses göra (here as gör) as a 'dummy verb' to fill that spot, much like how English uses 'do' for emphasis.

How does fronting väva change the tone of the sentence?

Placing väva at the very beginning of the sentence creates contrastive emphasis. The speaker is deliberately highlighting the action of weaving to set up a sharp contrast with the other action mentioned later, which is embroidering (broderat).

Why is the preposition på used in på fem år instead of i for the duration of five years?

Swedish uses på to express duration in negative statements. Because the second clause is negative (har inte broderat), you must use på to mean 'for five years'. If the sentence had been positive, meaning she actually had embroidered for five years, you would use i fem år instead.

Could I front the verb in the second clause as well to say Broderat har hon inte på fem år?