Fix llvmlite 0.45+ compatibility

Fixes #95 ## Summary Migrates from the deprecated Legacy Pass Manager API to the New Pass Manager API to fix compatibility with llvmlite 0.45.0 and later versions. ## Changes - Replaced `PassManagerBuilder` with `PipelineTuningOptions` and `PassBuilder` - Removed deprecated `llvm.initialize()` call (automatic in llvmlite >= 0.45) - Updated llvmlite requirement from `>=0.36` to `>=0.45` - Updated both `setup.py` and `environment.yml` ## Technical Details The Legacy Pass Manager was removed in llvmlite 0.45.0, causing: ``` AttributeError: module 'llvmlite.binding' has no attribute 'PassManagerBuilder' ``` The new implementation uses: - `PipelineTuningOptions(speed_level=3, size_level=0)` for optimization configuration - `PassBuilder` with target machine to create the module pass manager - Updated `pm_module.run(module, pb)` signature ## Testing All tests pass with llvmlite 0.45.1. 🤖 Generated with [Claude Code](https://claude.com/claude-code)