Promote current Fixars waitlist experience

[macaddy2]

Summary

• promotes the current Fixars waitlist experience to main
• adds course classification, a grouped micro-skill preview, and explicit profile/waitlist prefilling
• preserves the protected Google Form submission path and the existing product connector redirects
• refreshes the lockfile through the audit fix

Why

The live Fixars.ai page was serving an older waitlist build and did not let a taster selection populate the joining form.

Validation

• npm run build
• npm run test:sites (20 passing)
• npm audit --audit-level=high (0 vulnerabilities)
• browser verification: Computer Science -> Build preview -> Use in waitlist form; course and selected micro-skills populate the inline form
• 390px responsive smoke check