feat: implement random number generation

[mjm918]

Summary

Add random number generation to naml runtime for games, simulations, and general use.

Proposed API

// Generate random integer in range [min, max] inclusive
fn random(min: int, max: int) -> int;

// Generate random float in range [0.0, 1.0)
fn random_float() -> float;

Use Cases

• Games (random food placement, enemy behavior)
• Simulations
• Shuffling, sampling
• UUID generation

Implementation Notes

• Use a fast PRNG (xorshift, PCG, or similar)
• Seed from system entropy on startup
• Platform considerations:
  • Native: rand crate or custom PRNG
  • Server WASM: WASI random_get
  • Browser: Math.random() or WebCrypto

Acceptance Criteria

• random(min, max) returns integer in specified range
• random_float() returns float in [0.0, 1.0)
• Distribution is reasonably uniform
• Works on native platform

[mjm918]

Implemented. random() and random_float() available via use std::random::*;