Add Pybe (reimagined): case-study driven Python learning app

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What is this?

This is a reimagined take on the Pybe concept — a problem-first Python teaching
tool that introduces every construct through a vivid real-world case scenario,
rather than starting from syntax.

Key features

• Problem-based learning: every construct is taught through a case scenario first
• Rhizomatic exploration: learners build their own path rather than following a
  fixed curriculum
• Philosophical/metaphor-driven storytelling (e.g. exploring topics through
  Avengers, Harry Potter, Panchatantra lenses)
• In-browser code editor powered by Pyodide
• Socratic reveal: hints guide the learner, syntax is revealed only when they
  choose to see it
• Accessibility features: audio transcription, autocomplete, UI adapted to
  Piaget's cognitive development stages

Why it's added as a separate folder

This is a distinct implementation of the Pybe idea (not a modification of the
existing client/server app), so it's added under /pybe-reimagined to keep it
isolated and easy to review as its own concept.

What's included

• Full source (src/) — domain models, engine, agent, adapters, UI
• Content (content/) — case studies and concept graph data
• Test suite (tests/)
• Documentation (docs/, README.md, project_blueprint.md, context.md,
  future_scope.md)
• Config files (package.json, tsconfig.json, vite.config.ts, etc.)

What's excluded

• node_modules/ — regenerated via npm install
• dist/ — build output, regenerated via npm run build
• .github/workflows/ci.yml — GitHub Actions only reads workflows from the
  repo root, so this wasn't included here; happy to help wire up CI separately
  if maintainers want it