I’m happy to report, it’s likely a yes, an animal companion can be an ally.
From the index in the back,
ally An ally is someone on your side. You are not counted as your own ally. 456
Page 456 has information on allies in the top, saying:
Some effects target or require an ally, or otherwise refer to an ally. This must be someone on your side, often another PC, but it might be a bystander you are trying to protect. You are not your own ally. If it isn’t clear, the GM decides who counts as an ally or an enemy.
GM has final say. “Someone” might be ambiguous, and define a person as a qualifier for an ally, but it might be used here in the general sense too. So we look at the rest of the paragraph. Your animal companion fights on your side, and is not an enemy. If a bystander can be considered an ally, then an animal companion putting its life on the line for you fighting for you and accompanying you on adventures like other members of the party is certainly an ally.
But, is something that is your class feature and that uses your actions to function really a separate creature?
minion (trait) Minions are creatures that directly serve another creature. A creaturewith this trait can use only 2 actions per turn and can’t use reactions. Your minionacts on your turn in combat, once per turn, when you spend an action to issue itcommands. For an animal companion, you Command an Animal