Expose opt-level, features, libdevice and emit-stage options in warpforthc #120

Problem

warpforthc only exposes --arch and -o. The pipeline already has opt-level, features, libdevice and compilation-target in WarpForthPipelineOptions, but you can only reach them through warpforth-translate | warpforth-opt '--pass-pipeline=...'.

Proposal

Add matching flags to tools/warpforthc/warpforthc.cpp, for example:

• -O0 ... -O3 / --opt-level
• --features (PTX ISA version)
• --libdevice <path>
• optionally --emit=mlir|llvm|ptx to stop after a stage for debugging

Ideally warpforthc registers WarpForthPipelineOptions directly instead of duplicating each option, so the two tools can't drift apart.