chore: reorganize para current/, rails 8.1, testes e readme

- move app para current/ (estrutura capistrano)
- rails 7.2 → 8.1, ruby 3.2, sqlite3 2.x
- adiciona primary_key Idinformativo no model
- schema.rb completo com todas as tabelas
- testes minitest: models (Tag, Informativo, Tema) e controllers
- readme atualizado em pt-br com stack e instruções de desenvolvimento
- gitignore exclui dump.sql, *.duckdb e sqlite3

current/app/assets/stylesheets/active_admin.scss

@@ -0,0 +1,23 @@
+@import 'activeadmin_addons/all';
+// SASS variable overrides must be declared before loading up Active Admin's styles.
+//
+// To view the variables that Active Admin provides, take a look at
+// `app/assets/stylesheets/active_admin/mixins/_variables.scss` in the
+// Active Admin source.
+//
+// For example, to change the sidebar width:
+// $sidebar-width: 242px;
+
+// Active Admin's got SASS!
+@import "active_admin/mixins";
+@import "active_admin/base";
+
+//*= require trix
+.trix-button--icon-attach{
+  display: none
+}
+
+// Overriding any non-variable SASS must be done after the fact.
+// For example, to change the default status-tag color:
+//
+//   .status_tag { background: #6090DB; }