Allow MEoH resume from a checkpoint path

[er-s-an]

What changed

• add an optional checkpoint path to resume_meoh
• preserve the existing behavior by falling back to the profiler log directory when no path is supplied
• route population, profiler, and sample-order restoration through the selected checkpoint directory

Why

resume_meoh currently hard-codes pf._log_dir, so callers cannot resume a MEoH run from a different checkpoint directory. EoH and ReEvo already accept an explicit resume path. This adds the same capability without breaking existing no-argument calls.

Fixes #58.

Validation

• python3 -m py_compile llm4ad/method/meoh/resume.py
• isolated runtime test with stubbed MEoH dependencies: verified an explicit path is passed to all three restoration stages, restored state is assigned, and omitting the path still uses pf._log_dir

A full package import was not used for the runtime test because the local environment does not have the optional codebleu module imported by MEoH population code.