Fix validate-workflows.yml GitHub Actions workflow

[Copilot]

The validate-workflows.yml GitHub Actions workflow was broken and could not run successfully due to several issues:

Problems Fixed

Missing Dependencies & Directory Structure

• The workflow referenced a non-existent ./lib directory for dependency installation
• Attempted to install from missing requirements.txt file
• Used undefined n8n-validate and n8n-visualize commands that don't exist in the repository

Overly Complex Functionality

• Included visualization generation steps that required external tools not available in the repository
• Had complex artifact upload and PR commenting logic dependent on missing functionality

Solution

New Validation Script

• Created tools/validate_workflows.py that leverages the existing repository structure
• Validates JSON syntax of all workflow files (284 files processed successfully)
• Handles n8n export files with trailing metadata text (common in n8n workflow exports)
• Checks basic n8n workflow structure (presence of nodes array)
• Excludes known utility files (ALL_unique_nodes.json, all_templates.json)
• Provides clear error messages and supports verbose output mode

Simplified Workflow

• Removed dependency installation steps and non-existent tool calls
• Eliminated visualization creation and artifact upload functionality
• Streamlined PR commenting to focus on validation results
• Reduced workflow complexity from 134 lines to 79 lines

Testing

The updated workflow has been tested and:

• ✅ Successfully validates all 284 workflow files in the repository
• ✅ Properly detects and reports invalid JSON syntax
• ✅ Maintains proper exit codes for CI/CD integration
• ✅ YAML syntax validation passes

The workflow now uses only standard Python libraries and the existing repository structure, making it maintainable and reliable for continuous integration.

Original prompt

On validate-workflows.yml, ok

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✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

[github-actions]

✅ All 286 n8n workflow files are valid!

[Copilot]

Pull Request Overview

This PR fixes the broken validate-workflows.yml GitHub Actions workflow by creating a new Python validation script and simplifying the workflow configuration. The changes remove dependencies on non-existent tools and directories while maintaining proper JSON validation functionality.

• Creates a new tools/validate_workflows.py script that validates workflow JSON syntax and basic n8n structure
• Removes dependency installation steps and calls to undefined n8n-validate/n8n-visualize commands
• Simplifies workflow by removing visualization generation and artifact upload functionality

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
tools/validate_workflows.py	New Python validation script that checks JSON syntax and n8n workflow structure
.github/workflows/validate-workflows.yml	Simplified workflow that uses the new validation script instead of missing dependencies

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[Copilot]

This validation rule may be too strict. n8n allows workflows with empty nodes arrays as templates or incomplete workflows. Consider making this a warning rather than a hard error, or make it configurable via a command-line flag.

[Copilot]

Using errors='ignore' silently discards encoding errors which could mask data corruption issues. Consider using errors='replace' or errors='strict' with proper error handling to ensure data integrity during validation.

Suggested change

	with open(path, 'r', encoding='utf-8', errors='ignore') as f:
	with open(path, 'r', encoding='utf-8') as f: