feat: create jsonschema from zod

[LorisRue]

Summary

Implements generation of jsonschema directly from zod schema. Adds it to the npm run build command, so /template.schema.json is always up to date.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🧩 New template / stack support
• 💥 Breaking change (fix or feature that would cause existing functionality to change)
• 📚 Documentation update
• 🔧 Chore / dependency update

Related Issue

Closes #70

Changes Made

• Add new command: projgen schema to print json schema
• Expand build command to update template.schema.json file

Testing

• Ran npm run build — no errors
• Ran npm run lint — no lint errors
• Tested the CLI manually with npm link + projgen
• Tested on: Windows 11

Checklist

• My code follows the project's style (npm run lint passes)
• I have added / updated relevant documentation or comments
• My changes do not introduce new warnings
• I have read CONTRIBUTING.md