## Why
Rust v0 symbols can mention `codex_code_mode_host` as the instantiating crate of a dependency's generic function, so matching the crate name alone can select the wrong function.
## What changed
Demangle `nm` output and match `codex_code_mode_host::main` exactly, preserving spaces within demangled names. Include local symbols in the Linux lookup by removing `--extern-only`.
GitOrigin-RevId: b4ea4face3fe861966d3643d13db168143bcefa3