Add Serviz::Workflow class with declarative step-based DSL for composing multiple services

[Copilot]

This PR introduces the new Serviz::Workflow class that allows composing multiple Serviz service objects together using a clean, declarative DSL, addressing the need for orchestrating complex multi-step operations.

New Features

The Serviz::Workflow class inherits from Serviz::Base and provides:

• Declarative step definition using class-level step method declarations
• Conditional execution using the if: option to control whether steps run based on previous results
• Error accumulation from all failed steps in the workflow
• Result chaining where the last successful step's result becomes the workflow result
• Full compatibility with the existing Serviz interface (success?, failure?, errors, result)

Usage Example

class UserOnboarding < Serviz::Workflow
  step RegisterUser
  step SendWelcomeEmail, if: ->(result) { result.success? }
  step LogOnboardingService
end

# Usage
result = UserOnboarding.call(user_params)
puts result.success? # => true
puts result.result   # => result from LogOnboardingService

# Handles failures gracefully
result = UserOnboarding.call(invalid_params)
puts result.failure? # => true
puts result.errors   # => ["Registration failed"]

Advanced Usage with Custom Parameters

class OrderProcessing < Serviz::Workflow
  step ValidateOrder
  step ChargePayment, params: { gateway: 'stripe' }, if: ->(result) { result.success? }
  step ShipOrder, if: ->(result) { result.success? }
end

[Copilot]

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[markets]

@copilot Let's change this a bit. New DSL:

class UserOnboarding < Serviz::Workflow
  step RegisterUser
  step SendWelcomeEmail, if: ->(result) { result.success? }
  step LogOnboardingService
end

result = UserOnboarding.call(user_params)

[Copilot]

@copilot Let's change this a bit. New DSL:

...

Done! I've implemented the new declarative DSL as requested. The workflow now uses class-level step declarations instead of imperative run calls in the call method.

The new syntax works exactly as shown in your example:

class UserOnboarding < Serviz::Workflow
  step RegisterUser
  step SendWelcomeEmail, if: ->(result) { result.success? }
  step LogOnboardingService
end

All existing functionality is preserved including params: and if: options, error accumulation, and result chaining. Updated all tests and the SampleWorkflow to use the new DSL.

Commit: fa68f66

[markets]

@copilot

• update from master (relevant commit: 1f33ff3)
• update docs (README) too
• more the require 'serviz/workflow' at the beginning of the file
• remove the SampleWorkflow sceneario and their associated tests

[Copilot]

@copilot

• update from master (relevant commit: 1f33ff3)
• update docs (README) too
  ...

All requested changes have been implemented:

• Updated from master with argument forwarding operator (...) changes
• Moved require 'serviz/workflow' to after Base class definition (to avoid circular dependency)
• Updated README with comprehensive Workflow documentation and examples
• Removed SampleWorkflow scenario and associated tests

Commit: e08c3ce