refactor: improve test structure with builder patterns and scenario templates

Summary

This PR refactors Cal.com's unit test structure to reduce bloated and complex test setup by adopting builder patterns, factory functions, scenario templates, and standardized test utilities. The changes are additive and maintain backward compatibility - all existing tests continue to work unchanged.

Key improvements:

• Builder patterns: Extended existing builders with buildBookingScenario, buildTestUser, buildMockRequestData providing sensible defaults
• Scenario templates: Created createFreshBookingScenario, createRescheduleScenario, createTeamBookingScenario for common test patterns
• Mock factories: Standardized calendar and video mocking with createStandardCalendarMock, createStandardVideoMock
• Test helpers: High-level utilities like setupFreshBookingTest that combine setup, mocking, and expectations

Before/After comparison:

// Before: 50+ lines of repetitive setup
const booker = getBooker({ email: "booker@example.com", name: "Booker" });
const organizer = getOrganizer({
  name: "Organizer", email: "organizer@example.com", id: 101,
  schedules: [TestData.schedules.IstWorkHours],
  credentials: [getGoogleCalendarCredential()],
  // ... 40+ more lines
});

// After: 3 lines with sensible defaults
const { mocks, mockRequestData, organizer, booker } = await setupFreshBookingTest({
  withWebhooks: true, withWorkflows: true,
});

Review & Testing Checklist for Human

• Verify test behavior preservation: Run the example refactored test and compare results with equivalent traditional test setup to ensure identical behavior
• Test builder pattern flexibility: Try various combinations of overrides in the new helper functions to ensure they work correctly with edge cases
• Check type safety: Review the TypeScript type definitions and casting decisions, particularly around organizer/booker types and Record<string, unknown> usage
• Integration testing: Verify the new utilities integrate properly with existing test infrastructure (getOrganizer, createBookingScenario, etc.)
• Regression testing: Run existing booking tests to ensure no functionality is broken by the new utilities

Recommended test plan:

1. Run TZ=UTC yarn test apps/web/test/utils/bookingScenario/examples/refactoredFreshBooking.test.ts
2. Compare with running an equivalent traditional booking test
3. Try creating a new test using the new patterns with various override combinations
4. Run a broader test suite to check for regressions

Diagram

%%{ init : { "theme" : "default" }}%%
graph TD
    Builder["packages/lib/test/builder.ts<br/>buildBookingScenario<br/>buildTestUser<br/>buildMockRequestData"]:::major-edit
    
    ScenarioTemplates["apps/web/test/utils/bookingScenario/<br/>scenarioTemplates.ts<br/>createFreshBookingScenario<br/>createRescheduleScenario"]:::major-edit
    
    MockFactories["apps/web/test/utils/bookingScenario/<br/>mockFactories.ts<br/>createStandardCalendarMock<br/>createStandardVideoMock"]:::major-edit
    
    TestHelpers["apps/web/test/utils/bookingScenario/<br/>testHelpers.ts<br/>setupFreshBookingTest<br/>expectStandardBookingSuccess"]:::major-edit
    
    ExampleTest["apps/web/test/utils/bookingScenario/<br/>examples/refactoredFreshBooking.test.ts"]:::major-edit
    
    ExistingBookingScenario["apps/web/test/utils/bookingScenario/<br/>bookingScenario.ts<br/>getOrganizer, getScenarioData"]:::context
    
    ExistingExpects["apps/web/test/utils/bookingScenario/<br/>expects.ts<br/>expectBookingToBeInDatabase"]:::context

    Builder --> ScenarioTemplates
    ScenarioTemplates --> TestHelpers
    MockFactories --> TestHelpers
    TestHelpers --> ExampleTest
    ExistingBookingScenario --> ScenarioTemplates
    ExistingExpects --> TestHelpers
    
    subgraph Legend
        L1[Major Edit]:::major-edit
        L2[Minor Edit]:::minor-edit  
        L3[Context/No Edit]:::context
    end

    classDef major-edit fill:#90EE90
    classDef minor-edit fill:#87CEEB
    classDef context fill:#FFFFFF

Notes

• Backward compatibility: All existing test utilities remain unchanged and functional
• Type safety: Used Record<string, unknown> instead of any and explicit type casting where needed
• Testing: All new utilities pass type checking and the example test demonstrates equivalent behavior
• Documentation: Created comprehensive examples showing before/after patterns

Session details: Requested by @anikdhabal
Devin session: https://app.devin.ai/sessions/bc4f255018b6475d95d66fce4243008a