Add typed verl v0.8 OPD config compiler - #58

Summary

• add the typed verl-opd-v0.8-single-gpu-v1 config surface pinned to verl v0.8.0 at 7aed6b230776f963fa09509c10d9c3a767d1102c
• compile resolved YAML plus repeatable dotted --set overrides into a deterministic SHA-256-bound compatibility report
• classify every supplied leaf as exact, semantically conformant, locally reinterpreted, derived, informational only, or unsupported
• fail closed on PG OPD, task-reward mixtures, KL penalties, multiple generations/teachers, and distributed dimensions
• add an offline miniverl bridge compile-opd smoke that loads no weights and does not claim inference-engine or runtime equivalence

Scope boundary

This is PR A, the config/compiler layer only. config semantics executable: true means the supplied field set is inside the documented profile. The command explicitly reports that runtime execution is not provided by the config-only command. Parquet loading, prompt rollout, loss conformance, plan/run UX, and export arrive in later independently green PRs.

Validation

• non-GPU/non-network: 2,135 passed, 6 skipped, 21 deselected; 86.21% branch coverage
• GPU: 8 passed on the local RTX 4080
• network: 15 passed
• ruff check and format check
• mypy over src/miniverl and scripts
• actionlint 1.7.12
• strict MkDocs, Markdown links, text integrity, release-state and PyPI README checks
• wheel/sdist build and twine check
• frozen benchmark/evidence/preregistration diff against v0.7.1: clean
• calculator JSON SHA-256 remains 53fc1d4d5b7adee09618d77ad62d4086ba56b78569832d6fc7c3bcd5c2695bbc