[task] Extract validation methods from engine.go to engine_validation.go

[github-actions]

Objective

Extract validation methods from pkg/workflow/engine.go into a new dedicated validation file following the established *_validation.go pattern.

Context

The codebase follows a good pattern of having dedicated validation files (docker_validation.go, npm_validation.go, pip_validation.go), but validation methods in engine.go break this pattern, reducing discoverability. This is part of Issue #3 from the semantic function clustering analysis (Priority 2: Medium Impact, Medium Effort).

Related to #3478

Approach

1. Create new file pkg/workflow/engine_validation.go
2. Move validateEngine method from engine.go
3. Move validateSingleEngineSpecification method from engine.go
4. Ensure proper imports are in place
5. Update any internal references if needed
6. Verify all tests pass

Files to Modify

• Create: pkg/workflow/engine_validation.go
• Update: pkg/workflow/engine.go (remove validation methods)
• Update: Any test files that reference these methods

Acceptance Criteria

• New file engine_validation.go created
• validateEngine method moved to new file
• validateSingleEngineSpecification method moved to new file
• All imports correctly updated
• All existing tests pass
• No functionality broken
• File naming consistent with docker_validation.go, npm_validation.go pattern

Estimated Effort

1-2 hours

Benefits

• Improved discoverability of validation logic
• Consistent file organization across the codebase
• Follows established architectural patterns
• Easier to locate and maintain validation logic
  Related to [refactor] 🔧 Semantic Function Clustering Analysis - Refactoring Opportunities #3478

AI generated by Plan Command for #3478