BREAKING: torch/transformers moved from hard deps to [nli] optional group.
Consumer install is now ~5MB instead of ~2GB.

- Lazy torch import in scorer.py (no crash without torch)
- All "hardware interlock" language replaced with "software safety gate" (10 files)
- Deprecated 5 backward-compat aliases with DeprecationWarning
- CoherenceAgent defaults to VectorGroundTruthStore(InMemoryBackend)
- README rewritten: consumer-first, "What This Is / Is NOT" section
- New test_import_guard.py verifying no top-level torch import
- CI lightweight consumer test job (no torch)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>