Fix ArgumentError for text column length validations

`type_for_attribute(:description).limit` returns nil for text columns,
which newer Rails rejects with ArgumentError: :maximum must be a
non-negative Integer. Guard with `if type_for_attribute(...).limit`
to skip the validation when the column has no limit.

Affects Unit and Quantity models.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/models/quantity.rb

@@ -16,7 +16,7 @@ class Quantity < ApplicationRecord
   end
   validates :name, presence: true, uniqueness: {scope: [:user_id, :parent_id]},
     length: {maximum: type_for_attribute(:name).limit}
-  validates :description, length: {maximum: type_for_attribute(:description).limit}
+  validates :description, length: {maximum: type_for_attribute(:description).limit} if type_for_attribute(:description).limit
 
   # Update :depths of progenies after parent change
   before_save if: :parent_changed? do

app/models/unit.rb

@@ -13,7 +13,7 @@ class Unit < ApplicationRecord
   end
   validates :symbol, presence: true, uniqueness: {scope: :user_id},
     length: {maximum: type_for_attribute(:symbol).limit}
-  validates :description, length: {maximum: type_for_attribute(:description).limit}
+  validates :description, length: {maximum: type_for_attribute(:description).limit} if type_for_attribute(:description).limit
   validates :multiplier, numericality: {equal_to: 1}, unless: :base
   validates :multiplier, numericality: {greater_than: 0, precision: true, scale: true}, if: :base
 

db/seeds.rb

@@ -21,4 +21,3 @@ end
 #[Source, Quantity, Unit].each { |model| model.defaults.delete_all }
 
 require_relative 'seeds/units.rb'
-require_relative 'seeds/quantities.rb'

db/seeds/quantities.rb

@@ -1,9 +0,0 @@
-Quantity.transaction do
-  Quantity.defaults.delete_all
-
-  quantities = {}
-
-  quantities['Body weight'] =
-    Quantity.create name: 'Body weight',
-                    description: 'body weight measurement'
-end