As others have stated, the detention would appear to be objectively valid. The search ... not so slearly valid (beyond a pat-down for weapons, if minimal cause could be articulated).
At this point, you may have little more than a personnel complaint. And if they do not release dash cam videos (assuming there is one) as public records, you'd have to sue them to subpoena it. And, without any real damages, it might be expensive to pursue such a claim against the police department - and no attorney is likely to take this on contingency.

