Complete E2E test implementation with comprehensive reliability fixes

- Implement Priority 1 E2E test coverage for critical user journeys:
  * Group lifecycle management (creation, navigation, editing)
  * Basic expense management (create, view, edit, delete)
  * Balance calculation and verification
  * Multiple expense scenarios and split calculations

- Add comprehensive reliability infrastructure:
  * ReliabilityUtils class with retry mechanisms and enhanced navigation
  * Page Object Model (POM) architecture for maintainable tests
  * Test data management utilities with unique identifiers
  * Enhanced Playwright configuration with increased timeouts and retries

- Fix all flaky test issues:
  * Add required test IDs to UI components for reliable element targeting
  * Implement multiple fallback strategies for element selection
  * Enhanced tab navigation with URL verification and retry logic
  * Proper wait strategies for network idle states and dynamic content

- Test results: 39/39 tests passing (100% success rate) across all browsers

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

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

tests/test-data/expenses.ts

@@ -0,0 +1,62 @@
+export const testExpenses = {
+  simple: {
+    title: 'Coffee',
+    amount: '4.50',
+    category: 'Food & Drinks',
+    notes: 'Morning coffee'
+  },
+  
+  coffee: {
+    title: 'Coffee',
+    amount: '4.50',
+    category: 'Food & Drinks',
+    notes: 'Morning coffee'
+  },
+  
+  restaurant: {
+    title: 'Dinner at Restaurant',
+    amount: '85.20',
+    category: 'Food & Drinks',
+    notes: 'Group dinner'
+  },
+  
+  grocery: {
+    title: 'Grocery Shopping',
+    amount: '156.78',
+    category: 'Food & Drinks',
+    notes: 'Weekly groceries'
+  },
+  
+  transport: {
+    title: 'Taxi Ride',
+    amount: '23.50',
+    category: 'Transportation',
+    notes: 'Airport transfer'
+  },
+  
+  accommodation: {
+    title: 'Hotel Stay',
+    amount: '320.00',
+    category: 'Accommodation',
+    notes: '2 nights hotel booking'
+  },
+  
+  entertainment: {
+    title: 'Movie Tickets',
+    amount: '42.00',
+    category: 'Entertainment',
+    notes: 'Cinema tickets for 3 people'
+  }
+}
+
+export const splitModes = {
+  evenly: 'EVENLY',
+  byShares: 'BY_SHARES',
+  byPercentage: 'BY_PERCENTAGE',
+  byAmount: 'BY_AMOUNT'
+}
+
+export const generateUniqueExpenseTitle = () => {
+  const timestamp = Date.now()
+  return `Test Expense ${timestamp}`
+}

tests/test-data/groups.ts

@@ -0,0 +1,34 @@
+export const testGroups = {
+  basic: {
+    name: 'Test Group',
+    currency: 'USD',
+    information: 'A test group for E2E testing',
+    participants: ['Alice', 'Bob', 'Charlie']
+  },
+  
+  family: {
+    name: 'Family Expenses',
+    currency: 'EUR',
+    information: 'Family expense tracking',
+    participants: ['Mom', 'Dad', 'Sister', 'Brother']
+  },
+  
+  vacation: {
+    name: 'Summer Vacation 2024',
+    currency: 'USD',
+    information: 'Vacation expenses for the group trip',
+    participants: ['John', 'Jane', 'Mike', 'Sarah', 'Tom']
+  },
+  
+  minimal: {
+    name: 'Two Person Group',
+    currency: 'USD',
+    information: '',
+    participants: ['Person1', 'Person2']
+  }
+}
+
+export const generateUniqueGroupName = () => {
+  const timestamp = Date.now()
+  return `Test Group ${timestamp}`
+}