Challenge: Derive Multiple Related PDAs in Rust

Real Anchor programs often derive multiple PDAs per user — profile, stats, vault, etc. Each uses different seed prefixes but the same user key.

Using the simulated PDA derivation from earlier, derive 3 related PDAs and return their hashes as a tuple.

Your Task

Implement derive_user_pdas(user, program_id) that:

1. Derives a user PDA with seeds ["user", user]
2. Derives a stats PDA with seeds ["stats", user]
3. Derives a vault PDA with seeds ["vault", user]
4. Returns (user_hash, stats_hash, vault_hash) as a (u64, u64, u64) tuple

A helper find_pda is provided — use it to derive each PDA.

Requirements:

• All three hashes must be off-curve (even)
• All three must be different from each other
• Same inputs must always produce same outputs (deterministic)