Add NYASH_CLI_VERBOSE>=2 observation logs to trace the Ny compiler
child process path (NYASH_USE_NY_COMPILER=1):
- Log when spawning child process
- Log when receiving Program(JSON v0)
- Log before/after maybe_dump_mir with dump path info
- Report whether MIR dump file was created
Key finding: apps/selfhost/compiler/compiler.hako doesn't exist,
so the preferred child process route never fires. This explains
why RUST_MIR_DUMP_PATH doesn't create files in Ny compiler path.
Also update environment-variables.md with:
- NYASH_CLI_VERBOSE=2 level documentation
- Ny compiler observation template for Phase 29
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>