feat(regulatory-map): customer-readable read-model over the scope (step 4)

The Map Renderer explains the engine's state, it does not extend it. Pure
composition of resolve_product_scope (scope verdict) + derive_obligations
(registry-linked obligations + overlaps) into one RegulatoryMap.

- product_summary, trigger_facts, applicable/uncertain/excluded regulations,
  unsupported_domains, overlaps (shared_obligations), shared_evidence, and a
  customer-readable executive_summary.
- No own legal decisions: applicable/uncertain mirror the scope verdict exactly.
- Obligations shown ONLY when registry-linkable (registry_anchor) — MaschinenVO/
  EMV obligations are proposed, so they render empty + a note, never as linked.
  Overlaps/shared_evidence likewise filtered to registry-linked members.
- Uncertain regulations link to the navigator question that would resolve them
  (RED -> has_radio_module, DataAct -> generates_usage_data).
- Environmental appears only as unsupported_domain; executive_summary has NO
  percentage (counts + "no further regulations identified" instead).
- POST /reasoning/regulatory-map (thin handler). Response types are presentation-
  level, not meta-model classes (freeze v1.0 untouched).
- 9 tests; 56 green (existing reasoning MVP stays green), mypy clean, LOC ok.

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

backend-compliance/compliance/api/reasoning_routes.py

@@ -8,6 +8,7 @@ pure deterministic rule evaluation.
     POST /reasoning/implementation-reasoning   -> claim->obligation mapping (Welt 1, no verdict)
     POST /reasoning/interpretation-assessment  -> verdict on a customer interpretation
     POST /reasoning/product-scope              -> gate on facts, else run discover_scope once
+    POST /reasoning/regulatory-map             -> customer-readable read-model over the scope
 """
 
 from __future__ import annotations
@@ -19,6 +20,7 @@ from compliance.product_scope import (
     ProductScopeResponse,
     resolve_product_scope,
 )
+from compliance.regulatory_map import RegulatoryMap, RegulatoryMapRequest, render_regulatory_map
 from compliance.reasoning import (
     assess_interpretation,
     derive_obligations,
@@ -64,6 +66,11 @@ def product_scope(req: ProductScopeRequest) -> ProductScopeResponse:
     return resolve_product_scope(req.product_profile)
 
 
+@router.post("/regulatory-map", response_model=RegulatoryMap)
+def regulatory_map(req: RegulatoryMapRequest) -> RegulatoryMap:
+    return render_regulatory_map(req.product_profile)
+
+
 @router.post("/interpretation-assessment", response_model=InterpretationResponse)
 def interpretation_assessment(req: InterpretationRequest) -> InterpretationResponse:
     result = assess_interpretation(req.customer_interpretation, req.product_profile)