feat(reasoning): Regulatory Reasoning Engine MVP (scope/obligations/implementation/interpretation)

Deterministic reasoning layer ON TOP of the Legal Knowledge Graph (obligation
registry) and the Compliance Execution Graph (control mapping/evidence). Answers
which regulations apply to a concrete product, which obligations follow, whether
the customer's implementation covers them, and whether a customer interpretation
is too narrow/broad/plausible.

- ProductProfile with tri-state facts (Optional[bool]=None => uncertain, never
  false security); safe predicate evaluator (no eval).
- 6 regulation triggers (CRA/MaschinenVO/RED/EMV/DataAct/NIS2) with missing-fact
  prompts; 24 obligation scope rules.
- CRA obligation_ids RE-USED verbatim from the registry (93 ids) — never re-minted
  (control_uuid trap); Machine/Data-Act flagged proposed=True.
- required_evidence constrained to the framework-agnostic shared evidence catalog;
  capabilities echo the planned Obligation->Capability layer.
- Overlap groups (CRA<->MaschinenVO cyber-safety) + evidence-for-multiple (USP).
- 4 endpoints POST /reasoning/{scope,obligations,implementation-assessment,
  interpretation-assessment}; thin handlers, registered in api/__init__.py.
- 22 tests (5 machine-builder scenarios + 10 acceptance questions). No DB
  migration, no RAG, no new controls.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend-compliance/compliance/reasoning/__init__.py

@@ -0,0 +1,27 @@
+"""Regulatory Reasoning Engine.
+
+A deterministic reasoning layer ON TOP of the Legal Knowledge Graph (obligation
+registry) and the Compliance Execution Graph (control mapping / evidence). It
+answers, for a concrete product: which regulations apply, which obligations
+follow, whether the customer's implementation covers them, and whether a
+customer interpretation is legally sound.
+
+No new RAG, no new controls, no DB schema changes — scope & reasoning metamodel
+only (spec §14).
+"""
+
+from __future__ import annotations
+
+from .claim_normalizer import normalize_claim
+from .implementation_engine import assess_implementation
+from .interpretation_engine import assess_interpretation
+from .obligation_engine import derive_obligations
+from .scope_engine import discover_scope
+
+__all__ = [
+    "discover_scope",
+    "derive_obligations",
+    "normalize_claim",
+    "assess_implementation",
+    "assess_interpretation",
+]