remove most uses of as any in typescript

- replaced many uses of `as any` with another more specific cast `as T`
- filled in missing typed for items that needed to be typed
  - new runtime code was added where necessary to satisfy the new types with comments
- added missing theme variable "sidebar-active" to the Theme variables
- forms using `react-hook-form` are now typechecked
- changed some instances of `target` into `currentTarget` while removing `as any` assertions

src/pages/login/FormField.tsx

@@ -26,6 +26,8 @@ export default function FormField({
             )}
             <Localizer>
                 <InputBox
+                    // Styled uses React typing while we use Preact
+                    // this leads to inconsistances where things need to be typed oddly
                     placeholder={(<Text id={`login.enter.${type}`} />) as any}
                     name={
                         type === "current_password" ? "password" : name ?? type