Ensure Consistent Category Colors (#1722)

* feat: add validation to require consistent category color

* feat: reflect color requirement in new category form

* refactor: move logic inline over shared component

* rubocop

* tests: fix breaking and add case for new validation

* feat: hide color selector when parent category selected

* feat: override color with parent color in model

* tests: remove case for unnecessary validation

---------

Signed-off-by: Julien Bertazzo Lambert <42924425+JLambertazzo@users.noreply.github.com>

app/models/category.rb

@@ -14,6 +14,8 @@ class Category < ApplicationRecord
   validate :category_level_limit
   validate :nested_category_matches_parent_classification
 
+  before_create :inherit_color_from_parent
+
   scope :alphabetically, -> { order(:name) }
   scope :roots, -> { where(parent_id: nil) }
   scope :incomes, -> { where(classification: "income") }
@@ -85,6 +87,12 @@ class Category < ApplicationRecord
       end
   end
 
+  def inherit_color_from_parent
+    if subcategory?
+      self.color = parent.color
+    end
+  end
+
   def replace_and_destroy!(replacement)
     transaction do
       transactions.update_all category_id: replacement&.id