v0-course-desginer

export: add Back to plan on completion screen, drop redundant 'Export another format'

fix: backward nav skips plan generation; export Public Link is real

landing: 'see a sample' routes through the prefilled wizard

fix: Start a course resets state, sample CTA stays read-only, Suggest 3 randomizes

fix: outcome coverage 0/5 + template flow skips slow generation animations