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/models/admin_user.rb

@@ -0,0 +1,10 @@
+class AdminUser < ApplicationRecord
+  # Include default devise modules. Others available are:
+  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
+  devise :database_authenticatable, 
+         :recoverable, :rememberable, :validatable
+  # Include default devise modules. Others available are:
+  # :confirmable, :lockable, :timeoutable, :trackable and :omniauthable
+  devise :database_authenticatable, 
+         :recoverable, :rememberable, :validatable
+end