Fix Rails 7+ mutating forum actions by replacing method links with button forms

[aliumairdev]

Problem

Mutating forum actions relied on link_to ... method: (delete post, mark solved/unsolved, notification toggle). In Rails 7+ setups without rails-ujs, these links fall back to GET and the intended POST/PUT/DELETE actions do not execute.

Root Cause

link_to with method: depends on JavaScript interception via data-method.

Fix

• Replace mutating link_to ... method: calls with button_to in:
  • forum post partial (delete, solved, unsolved)
  • discussion layout notification toggle
• Keep the existing UI styling via button classes/form_class.

Tests

• Added test/views/non_js_actions_test.rb to assert these mutating actions use button_to and no longer use link_to ... method:.
• Ran:
  • bundle _2.7.1_ exec ruby test/views/non_js_actions_test.rb
  • bundle _2.7.1_ exec standardrb test/views/non_js_actions_test.rb

Fixes #41