[WIP] Add openapi schema validator

[Copilot]

• Explore repository structure and understand codebase
• Install @seriousme/openapi-schema-validator dependency
• Test current schema validation and identify existing issues
• Add validation function to main.ts after schema generation
• Create separate validation script for CI workflow
• Add validation step to CI workflow
• Fix OAuth2 security scheme to include required flows property
• Handle ES module import issues in tests by isolating validator
• Add environment variable to skip validation when needed
• Optionally fix remaining schema validation issues

Successfully implemented OpenAPI schema validation that:

• Validates generated dist/schema.json after generation
• Can be run separately via npm run validate
• Integrated into CI workflow
• Fixed OAuth2 security scheme to be valid OpenAPI 3.0.3
• Current schema has one remaining issue: unresolved #/components/schemas/Field reference

Fixes #26.

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.