Added config validation

[joebm218]

What

Added Validations for .g0.yaml,.g0-policy.yaml,.g0-risk-acceptance.yaml based on presets and severities

Why

Link to an issue: "Fixes #85 "

How

Type of Change

• Bug fix
• New feature / enhancement
• Security fix (dependency update, vulnerability patch)

Testing

• Added / updated unit tests (npm test passes)
• Build succeeds (npm run build)
• Manually tested against a real agent project (if applicable)

Security Checklist (for rule additions or code changes)

• No secrets or credentials in code or tests
• New rules have compliant + vulnerable examples
• No new ReDoS-prone regexes (test with ReDoS checker if in doubt)
• No sensitive data logged to console

Breaking Changes

None

Checklist

• Follows existing code patterns and style
• No unnecessary new dependencies (or justified above)
• Self-reviewed the diff before requesting review