Fix review issues in cookie pattern handling

- Fix DurationInput fallback unit from "minutes" to "seconds" and add
  seconds as a selectable unit to prevent silent duration inflation
- Use parseFloat instead of parseInt for duration input to preserve
  fractional values
- Scope prefix merge groups by category ID to prevent cross-category
  merging
- Relink cookies and delete exact patterns even when prefix pattern
  already exists
- Prefer exact matches and longest prefix in pattern selection query
- Fix wrong error type in GetCookiePattern (ErrCookiePatternNotFound)
- Handle singular/plural in humanizeSeconds fallback branch

Signed-off-by: Émile Ré <emile@getprobo.com>

pkg/cookiebanner/service.go

@@ -1375,7 +1375,7 @@ func (s *Service) GetCookiePattern(
 		func(ctx context.Context, conn pg.Querier) error {
 			if err := pattern.LoadByID(ctx, conn, scope, cookiePatternID); err != nil {
 				if errors.Is(err, coredata.ErrResourceNotFound) {
-					return ErrCookieNotFound
+					return ErrCookiePatternNotFound
 				}
 				return fmt.Errorf("cannot load cookie pattern: %w", err)
 			}