Add isolated Fixars product sites and deployment architecture

[macaddy2]

What changed

• adds isolated SkillsCanvas, ConceptsNexus, CollaBoard, and VestDen site source and reproducible static artifacts
• adds versioned ecosystem event contracts and the approved network/webhook architecture
• adds a cPanel deployment manifest that copies only each product artifact to its isolated canonical document root
• adds CI for dependency audit, architecture validation, reproducible builds, and artifact drift
• corrects canonical product casing in the repository overview

Why

The four products need independent canonical domains while remaining connected through Fixars.ai aliases and later event-driven integrations. This keeps Fixars.ai, its waitlist, and FixarsGroup.com outside the product deployment boundary.

Validation

• npm audit --audit-level=high — 0 vulnerabilities
• npm run architecture:validate — 9 versioned events across 6 bounded products/services
• npm run build:products — all four isolated artifacts built successfully
• credential-pattern scan across all scoped publish files — clean

Deployment impact

The cPanel manifest targets only the four existing, empty canonical product roots. Connector subdomains remain permanent redirects and are not duplicate app origins.