[plan] Fix schema validation gaps from conditional logic analysis

[github-actions]

Overview

This tracking issue covers fixing schema validation gaps discovered in the conditional logic analysis (Discussion #5799). The analysis found 3 critical issues and 2 moderate issues related to array constraints, field definitions, and GitHub Actions filter compatibility.

Source: Discussion #5799

Issues Identified

Critical (3)

1. Empty schedule arrays accepted - Missing minItems: 1 constraint
2. Strict mode field missing from schema - Implemented but not defined in schema
3. Draft + ready_for_review logical conflict - No validation for conflicting states

Moderate (2)

4. Branches/branches-ignore mutual exclusivity - GitHub Actions requirement not validated
5. Paths/paths-ignore mutual exclusivity - GitHub Actions requirement not validated

Planned Tasks

The work is broken down into 5 focused sub-issues:

1. Add minItems constraint to schedule array
2. Add strict mode field definition to schema
3. Document branches/paths mutual exclusivity with comments
4. Add draft/ready_for_review state documentation
5. Implement compiler validation for filter mutual exclusivity

Each task includes specific file locations, code changes, and acceptance criteria.

References

• Analysis Discussion: [Schema Consistency] Conditional Logic Analysis - Dec 8, 2025: Schedule Array, Strict Mode, and Filter Exclusivity Gaps #5799
• Schema File: pkg/parser/schemas/main_workflow_schema.json
• Validation Logic: pkg/parser/schema.go, pkg/workflow/compiler.go

AI generated by Plan Command for discussion #5799