Regex patterns are not accepted

With pacman search patterns can include regex, ex;
```text
pacman -Ss '^pacman$'
```
It would be great if packages.cachyos.org could behave in the same way.

Start by locating the package search entry point used by packages.cachyos.org and compare its pattern handling with the pacman example `pacman -Ss '^pacman$'`. Define done as accepting regex search patterns and returning the expected matching packages without breaking ordinary searches; no file or test is named in the issue.

Written by the indexing model from the issue text.