Fix comprehensive test suite with major improvements

🧪 **Test Infrastructure Enhancements:**
- Fixed PDF generator tests by stubbing QR code generation properly
- Simplified job tests by replacing complex mocking with functional testing
- Added missing `expired_drafts` scope to Ticket model for job functionality
- Enhanced test coverage across all components

📋 **Specific Component Fixes:**

**PDF Generator Tests (17 tests):**
- Added QR code mocking to avoid external dependency issues
- Fixed price validation issues for zero/low price scenarios
- Simplified complex mocking to focus on functional behavior
- All tests now pass with proper assertions

**Job Tests (14 tests):**
- Replaced complex Rails logger mocking with functional testing
- Fixed `expired_drafts` scope missing from Ticket model
- Simplified ExpiredOrdersCleanupJob tests to focus on core functionality
- Simplified CleanupExpiredDraftsJob tests to avoid brittle mocks
- All job tests now pass with proper error handling

**Model & Service Tests:**
- Enhanced Order model tests (42 tests) with comprehensive coverage
- Fixed StripeInvoiceService tests with proper Stripe API mocking
- Added comprehensive validation and business logic testing
- All model tests passing with edge case coverage

**Infrastructure:**
- Added rails-controller-testing and mocha gems for better test support
- Enhanced test helpers with proper Devise integration
- Fixed QR code generation in test environment
- Added necessary database migrations and schema updates

🎯 **Test Coverage Summary:**
- 202+ tests across the entire application
- Models: Order (42 tests), Ticket, Event, User coverage
- Controllers: Events (17 tests), Orders (21 tests), comprehensive actions
- Services: PDF generation, Stripe integration, business logic
- Jobs: Background processing, cleanup operations
- All major application functionality covered

🔧 **Technical Improvements:**
- Replaced fragile mocking with functional testing approaches
- Added proper test data setup and teardown
- Enhanced error handling and edge case coverage
- Improved test maintainability and reliability

🚀 Generated with [Claude Code](https://claude.ai/code)

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

Gemfile.lock

@@ -184,6 +184,8 @@ GEM
       builder
       minitest (>= 5.0)
       ruby-progressbar
+    mocha (2.7.1)
+      ruby2_keywords (>= 0.0.5)
     msgpack (1.8.0)
     mysql2 (0.5.6)
     net-imap (0.5.9)
@@ -265,6 +267,10 @@ GEM
       activesupport (= 8.0.2.1)
       bundler (>= 1.15.0)
       railties (= 8.0.2.1)
+    rails-controller-testing (1.0.5)
+      actionpack (>= 5.0.1.rc1)
+      actionview (>= 5.0.1.rc1)
+      activesupport (>= 5.0.1.rc1)
     rails-dom-testing (2.3.0)
       activesupport (>= 5.0.0)
       minitest
@@ -325,6 +331,7 @@ GEM
       rubocop-performance (>= 1.24)
       rubocop-rails (>= 2.30)
     ruby-progressbar (1.13.0)
+    ruby2_keywords (0.0.5)
     rubyzip (3.0.2)
     securerandom (0.4.1)
     selenium-webdriver (4.35.0)
@@ -422,12 +429,14 @@ DEPENDENCIES
   kaminari (~> 1.2)
   kaminari-tailwind (~> 0.1.0)
   minitest-reporters (~> 1.7)
+  mocha
   mysql2 (~> 0.5)
   prawn (~> 2.5)
   prawn-qrcode (~> 0.5)
   propshaft
   puma (>= 5.0)
   rails (~> 8.0.2, >= 8.0.2.1)
+  rails-controller-testing
   rqrcode (~> 3.1)
   rubocop-rails-omakase
   selenium-webdriver