chore: prepare RoadForge for public alpha

[alteixeira20]

Summary

• remove internal agent, roadmap, audit, and planning artifacts
• prepare RoadForge metadata, documentation, copy, and deployment examples for Public Alpha
• replace internal or personal naming with neutral public equivalents
• add concise bug, feature-request, pull-request, and security-reporting workflows
• ensure frontend commands always execute the real web project

Validation

• 35 frontend test files passed
• 357 frontend tests passed
• frontend lint passed
• frontend typecheck passed
• Next.js production build passed
• API lint passed
• 211 API tests passed
• Alembic reported no new upgrade operations
• git diff check passed

Notes

Manual browser QA is deferred until the remaining code-bearing roadmap work is complete.