feat: implement rescheduling workflows as background job

[sean-brydon]

What does this PR do?

Implements rescheduling workflows as a background job using the existing email/SMS tasker pattern as inspiration. This moves workflow scheduling for reschedule events to trigger.dev for async execution, reducing latency in the booking response.

The implementation follows the same 3-layer architecture used by BookingEmailAndSmsTasker:

• WorkflowTasker - Main orchestrator that dispatches to async or sync tasker
• WorkflowTriggerDevTasker - Async implementation via trigger.dev
• WorkflowSyncTasker - Sync fallback implementation
• WorkflowTaskService - Contains the actual business logic (calls scheduleWorkflowReminders)

Key changes:

• Added workflow-tasker feature flag to AppFlags
• Created DI modules and tokens for workflow tasker components
• Added getBookingForWorkflowTasker repository method to fetch booking data with required relations
• Integrated WorkflowTasker into RegularBookingService for reschedule events
• Created trigger.dev task workflow.schedule.reschedule
• Added comprehensive unit tests (27 tests across 4 test files)

The feature is gated behind the workflow-tasker feature flag and only triggers for organizations that have the flag enabled.

Mandatory Tasks (DO NOT REMOVE)

• I have self-reviewed the code (A decent size PR without self-review might be rejected).
• I have updated the developer docs in /docs if this PR makes changes that would require a documentation change. N/A - no docs changes needed.
• I confirm automated tests are in place that prove my fix is effective or that my feature works.

How should this be tested?

1. Enable the workflow-tasker feature flag for a test organization
2. Create a booking with a workflow that triggers on RESCHEDULE_EVENT
3. Reschedule the booking
4. Verify the workflow is scheduled via trigger.dev (check trigger.dev dashboard)
5. Verify the workflow executes correctly (email/SMS sent)

Environment variables needed:

• TRIGGER_API_KEY and TRIGGER_API_URL for trigger.dev integration
• Feature flag workflow-tasker must be enabled for the org

Checklist for Human Review

• Verify ExtendedCalendarEvent construction in WorkflowTaskService matches what scheduleWorkflowReminders expects
• Check if task registration in packages/features/tasker/tasks/index.ts is needed for trigger.dev
• Review workflow filtering logic - currently includes RESCHEDULE_EVENT, BEFORE_EVENT, and AFTER_EVENT triggers
• Review indentation changes in RegularBookingService.ts, BookingRepository.ts, and config.ts - some appear to be formatting-only changes that may need cleanup

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Link to Devin run: https://app.devin.ai/sessions/43d17dbab131473883f6421be9ebc5fd
Requested by: @sean-brydon

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