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/clean_slate.rb

@@ -0,0 +1,126 @@
+# Clean slate scenario - minimal starter data for new user onboarding
+#
+# This scenario creates the absolute minimum data needed to help new users
+# understand Maybe's core features without overwhelming them. Ideal for:
+# - New user onboarding flows
+# - Tutorial walkthroughs
+# - Clean development environments
+# - User acceptance testing with minimal data
+#
+# The scenario only generates data when explicitly requested via with_minimal_data: true,
+# otherwise it creates no data at all (true "clean slate").
+#
+# @example Minimal data generation
+#   scenario = Demo::Scenarios::CleanSlate.new(generators)
+#   scenario.generate!(families, with_minimal_data: true)
+#
+# @example True clean slate (no data)
+#   scenario = Demo::Scenarios::CleanSlate.new(generators)
+#   scenario.generate!(families) # Creates nothing
+#
+class Demo::Scenarios::CleanSlate < Demo::BaseScenario
+  # Scenario characteristics and configuration
+  SCENARIO_NAME = "Clean Slate".freeze
+  PURPOSE = "Minimal starter data for new user onboarding and tutorials".freeze
+  TARGET_ACCOUNTS_PER_FAMILY = 1 # Single checking account only
+  TARGET_TRANSACTIONS_PER_FAMILY = 3 # Just enough to show transaction history
+  INCLUDES_SECURITIES = false
+  INCLUDES_TRANSFERS = false
+  INCLUDES_RULES = false
+  MINIMAL_CATEGORIES = 2 # Essential expense and income categories only
+
+  # Override the base generate! method to handle the special with_minimal_data option
+  # Only generates data when explicitly requested to avoid accidental data creation
+  #
+  # @param families [Array<Family>] Families to generate data for
+  # @param options [Hash] Options hash that may contain with_minimal_data or require_onboarding
+  def generate!(families, **options)
+    # For "empty" task, don't generate any data
+    # For "new_user" task, generate minimal data for onboarding users
+    with_minimal_data = options[:with_minimal_data] || options[:require_onboarding]
+    return unless with_minimal_data
+
+    super(families, **options)
+  end
+
+  private
+
+    # Generate minimal family data for getting started
+    # Creates only essential accounts and transactions to demonstrate core features
+    #
+    # @param family [Family] The family to generate data for
+    # @param options [Hash] Additional options (with_minimal_data used for validation)
+    def generate_family_data!(family, **options)
+      create_essential_categories!(family)
+      create_primary_checking_account!(family)
+      create_sample_transaction_history!(family)
+    end
+
+    # Create only the most essential categories for basic expense tracking
+    def create_essential_categories!(family)
+      @food_category = family.categories.create!(
+        name: "Food & Drink",
+        color: "#4da568",
+        classification: "expense"
+      )
+
+      @income_category = family.categories.create!(
+        name: "Income",
+        color: "#6471eb",
+        classification: "income"
+      )
+
+      puts "  - #{MINIMAL_CATEGORIES} essential categories created"
+    end
+
+    # Create a single primary checking account with a reasonable starting balance
+    def create_primary_checking_account!(family)
+      @checking_account = family.accounts.create!(
+        accountable: Depository.new,
+        name: "Main Checking",
+        balance: 0, # Will be calculated from transactions
+        currency: "USD"
+      )
+
+      puts "  - #{TARGET_ACCOUNTS_PER_FAMILY} primary checking account created"
+    end
+
+    # Create minimal transaction history showing income and expense patterns
+    def create_sample_transaction_history!(family)
+      # Recent salary deposit
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: -3000, # Income (negative = inflow)
+        name: "Salary",
+        category: @income_category,
+        date: 15.days.ago
+      )
+
+      # Recent grocery purchase
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: 75, # Expense (positive = outflow)
+        name: "Grocery Store",
+        category: @food_category,
+        date: 5.days.ago
+      )
+
+      # Recent restaurant expense
+      @generators[:transaction_generator].create_transaction!(
+        account: @checking_account,
+        amount: 45, # Expense
+        name: "Restaurant",
+        category: @food_category,
+        date: 2.days.ago
+      )
+
+      # Update account balance to match transaction sum
+      @generators[:transaction_generator].update_account_balances_from_transactions!(family)
+
+      puts "  - #{TARGET_TRANSACTIONS_PER_FAMILY} sample transactions created"
+    end
+
+    def scenario_name
+      SCENARIO_NAME
+    end
+end