feat: migrate portal to Hugo catalog with Supabase data

[marcelo-m7]

Summary

• replace the Next.js remnants with Hugo configuration tuned for Portuguese by default, update the README, and secure access to Supabase environment variables
• restructure the content tree into courses/UCs/topics with dedicated Hugo layouts and a browser Supabase client that hydrates course, UC, and topic pages
• add automated frontmatter validation, markdown-to-Supabase sync scripts, and database migrations plus seeds for the initial catalog sample

Testing

• npm run validate:frontmatter
• npm run build

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https://chatgpt.com/codex/tasks/task_e_68cd46ecf7d483228bd25c0e39286ae9