feat: example env files are listed hidden, not skipped

.env.example, .sample, .template and the like show with H: someone may
have put a real value in one. They're left out of sharing a repo's env
files.

internal/ui/app/sharefiles.go

@@ -71,7 +71,7 @@ func (m *Model) shareFiles(src provider.Source, cs []provider.Container) tea.Cmd
 				return msg
 			}
 			for _, c := range all {
-				if c.Detail == provider.DetailPlainEnv {
+				if c.Detail == provider.DetailPlainEnv && !c.Hidden { // not .env.example
 					cs = append(cs, c)
 				}
 			}