Learn: Add curriculum index — organize recipes and guides into beginner→expert paths

[PetarStoev02]

Context

The learn repo is accumulating recipes and guides at a healthy clip, but a new learner landing here has no path through them — just a list. A curriculum index turns the collection into something usable from day one, and lays the foundation for the future LMS platform that will sit on top of this content.

What to build

Add a top-level CURRICULUM.md (or INDEX.md) that groups existing recipes and guides into four progressive paths:

1. Beginner — blockchain basics, wallets, reading from a contract
2. Intermediate — deploying, price feeds, events, multi-chain
3. Advanced — DeFi, NFTs, L2/rollups, gas, security
4. Expert — MEV, flash loans, formal verification, cross-chain messaging

For each path:

• One-paragraph intro covering what the learner will be able to do after
• Ordered list of recipes/guides with their links and a one-line "what you'll learn" each
• Prerequisites pointing back to earlier paths

The structure should be machine-readable enough that the future LMS can lift it directly.

Acceptance criteria

• CURRICULUM.md exists at the repo root
• All existing recipes/guides are placed in exactly one path
• Each entry has a "what you'll learn" line
• Each path has prerequisites and an intro
• README links to the curriculum prominently

Pointers

• Related project context: w3-kit's LMS vision (free content + optional paid interactive layer)
• Reference: Patrick Collins' Cyfrin Updraft course structure

Complexity

🟡 Intermediate