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/config/initializers/activeadmin_addons.rb

@@ -0,0 +1,12 @@
+ActiveadminAddons.setup do |config|
+  # Change to "default" if you want to use ActiveAdmin's default select control.
+  # config.default_select = "select2"
+
+  # Set default options for DateTimePickerInput. The options you can provide are the same as in
+  # xdan's datetimepicker library (https://github.com/xdan/datetimepicker/tree/2.5.4). Yo need to
+  # pass a ruby hash, avoid camelCase keys. For example: use min_date instead of minDate key.
+  # config.datetime_picker_default_options = {}
+
+  # Set DateTimePickerInput input format. This if for backend (Ruby)
+  # config.datetime_picker_input_format = "%Y-%m-%d %H:%M"
+end