Merchants improvements (#594)

* FIX logos

* Implement merchant mods

* FIX confirm issue

* FIX linter

* Add recently seen merchants to re-add if needed

* Update merge.html.erb

* FIX do security check

* Add error handling for update failures.

db/migrate/20260109135841_add_website_url_to_securities.rb

@@ -0,0 +1,5 @@
+class AddWebsiteUrlToSecurities < ActiveRecord::Migration[7.2]
+  def change
+    add_column :securities, :website_url, :string
+  end
+end

db/migrate/20260109144012_create_family_merchant_associations.rb

@@ -0,0 +1,13 @@
+class CreateFamilyMerchantAssociations < ActiveRecord::Migration[7.2]
+  def change
+    create_table :family_merchant_associations, id: :uuid do |t|
+      t.references :family, null: false, foreign_key: true, type: :uuid
+      t.references :merchant, null: false, foreign_key: true, type: :uuid
+      t.datetime :unlinked_at
+
+      t.timestamps
+    end
+
+    add_index :family_merchant_associations, [ :family_id, :merchant_id ], unique: true
+  end
+end