Add `lux compile <file>` command that compiles and runs Lux code using
the Cranelift JIT compiler. Includes --benchmark flag for timing.
- Add compile_file() function in main.rs
- Add jit_test.lux example with fib(30) + factorial(10)
- Update VISION.md status
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
