Realistic demo data for performance testing (#2361)

* Realistic demo data for performance testing

* Add note about performance testing

* Fix bugbot issues

* More realistic account values

app/models/demo/scenarios/basic_budget.rb

@@ -0,0 +1,129 @@
+# Basic budget scenario - minimal budgeting demonstration with categories
+#
+# This scenario creates a simple budget demonstration with parent/child categories
+# and one transaction per category. Designed to showcase basic budgeting features
+# without overwhelming complexity. Ideal for:
+# - Basic budgeting feature demos
+# - Category hierarchy demonstrations
+# - Simple transaction categorization examples
+# - Lightweight testing environments
+#
+class Demo::Scenarios::BasicBudget < Demo::BaseScenario
+  include Demo::DataHelper
+
+  # Scenario characteristics and configuration
+  SCENARIO_NAME = "Basic Budget".freeze
+  PURPOSE = "Simple budget demonstration with category hierarchy".freeze
+  TARGET_ACCOUNTS_PER_FAMILY = 1 # Single checking account
+  TARGET_TRANSACTIONS_PER_FAMILY = 4 # One income, three expenses
+  TARGET_CATEGORIES = 4 # Income + 3 expense categories (with one subcategory)
+  INCLUDES_SECURITIES = false
+  INCLUDES_TRANSFERS = false
+  INCLUDES_RULES = false
+
+  private
+
+    # Generate basic budget demonstration data
+    # Creates simple category hierarchy and one transaction per category
+    #
+    # @param family [Family] The family to generate data for
+    # @param options [Hash] Additional options (unused in this scenario)
+    def generate_family_data!(family, **options)
+      create_category_hierarchy!(family)
+      create_demo_checking_account!(family)
+      create_sample_categorized_transactions!(family)
+    end
+
+    # Create parent categories with one subcategory example
+    def create_category_hierarchy!(family)
+      # Create parent categories
+      @food_category = family.categories.create!(
+        name: "Food & Drink",
+        color: random_color,
+        classification: "expense"
+      )
+
+      @transport_category = family.categories.create!(
+        name: "Transportation",
+        color: random_color,
+        classification: "expense"
+      )
+
+      # Create subcategory to demonstrate hierarchy
+      @restaurants_category = family.categories.create!(
+        name: "Restaurants",
+        parent: @food_category,
+        color: random_color,
+        classification: "expense"
+      )
+
+      puts "  - #{TARGET_CATEGORIES} categories created (with parent/child hierarchy)"
+    end
+
+    # Create single checking account for budget demonstration
+    def create_demo_checking_account!(family)
+      @checking_account = family.accounts.create!(
+        accountable: Depository.new,
+        name: "Demo Checking",
+        balance: 0, # Will be calculated from transactions
+        currency: "USD"
+      )
+
+      puts "  - #{TARGET_ACCOUNTS_PER_FAMILY} demo checking account created"
+    end
+
+    # Create one transaction for each category to demonstrate categorization
+    def create_sample_categorized_transactions!(family)
+      # Create income category and transaction first
+      income_category = family.categories.create!(
+        name: "Income",
+        color: random_color,
+        classification: "income"
+      )
+
+      # Add income transaction (negative amount = inflow)
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: -500, # Income (negative)
+        name: "Salary",
+        category: income_category,
+        date: 5.days.ago
+      )
+
+      # Grocery transaction (parent category)
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: 100,
+        name: "Grocery Store",
+        category: @food_category,
+        date: 2.days.ago
+      )
+
+      # Restaurant transaction (subcategory)
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: 50,
+        name: "Restaurant Meal",
+        category: @restaurants_category,
+        date: 1.day.ago
+      )
+
+      # Transportation transaction
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: 20,
+        name: "Gas Station",
+        category: @transport_category,
+        date: Date.current
+      )
+
+      # Update account balance to match transaction sum
+      @generators[:transaction_generator].update_account_balances_from_transactions!(family)
+
+      puts "  - #{TARGET_TRANSACTIONS_PER_FAMILY + 1} categorized transactions created (including income)"
+    end
+
+    def scenario_name
+      SCENARIO_NAME
+    end
+end