refactor(reasoning): enforce ClaimCoverage (Welt 1) vs ComplianceStatus (Welt 2) boundary [F1]

Architecture-validation finding: the implementation mode produced compliance-
flavored output ("teilweise erfüllt", "covered") from a mere customer claim,
blurring the line to the Execution layer. This is a design decision, not a text
fix — the reasoning layer judges only the customer's STATEMENT, never conformity.

- CoverageStatus -> ClaimCoverage; values are claim-relative + carry "potential":
  potentially_addresses / partially_addresses / does_not_address /
  insufficient_information.
- ImplementationAssessment -> ClaimObligationMapping (coverage_status ->
  claim_coverage); ImplementationResponse -> ImplementationReasoningResponse
  (assessments -> mappings, + explicit `disclaimer`); request renamed; engine
  entry assess_implementation -> reason_implementation_claim.
- Endpoint /reasoning/implementation-assessment -> /reasoning/implementation-reasoning.
- Summary/explanations reworded: "adressiert wahrscheinlich N Pflichten … für
  eine Bewertung der tatsächlichen Umsetzung sind Nachweise erforderlich (keine
  Konformitätsaussage)". No "erfüllt"/"abgedeckt" leaks.
- New guard test asserts no compliance verdict leaks (no "erfüllt"; disclaimer
  separates ClaimCoverage from ComplianceStatus). 23 tests green, mypy clean.

Discovery (scope/obligations) was already structurally claim-free and unaffected.

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

backend-compliance/compliance/reasoning/schemas.py

@@ -15,8 +15,8 @@ from pydantic import BaseModel, Field
 from .enums import (
     ApplicabilityStatus,
     AuthorityLevel,
+    ClaimCoverage,
     Confidence,
-    CoverageStatus,
     InterpretationVerdict,
     ManufacturerRole,
     MarketModel,
@@ -140,10 +140,17 @@ class CustomerImplementationClaim(BaseModel):
     evidence_refs: List[str] = Field(default_factory=list)
 
 
-class ImplementationAssessment(BaseModel):
+class ClaimObligationMapping(BaseModel):
+    """One row of Welt-1 reasoning: how a customer claim relates to an obligation.
+
+    Layers (spec / architect): claim -> interpretation (on the claim object) ->
+    *potential* obligation coverage (`claim_coverage`) -> evidence required.
+    Carries NO compliance verdict.
+    """
+
     claim_id: str
     obligation_id: str
-    coverage_status: CoverageStatus
+    claim_coverage: ClaimCoverage
     missing_elements: List[str] = Field(default_factory=list)
     required_evidence: List[str] = Field(default_factory=list)
     explanation: str
@@ -188,16 +195,19 @@ class ObligationsResponse(BaseModel):
     evidence_for_multiple: Dict[str, List[str]] = Field(default_factory=dict)
 
 
-class ImplementationRequest(BaseModel):
+class ImplementationReasoningRequest(BaseModel):
     product_profile: ProductProfile
     customer_claim: str
 
 
-class ImplementationResponse(BaseModel):
+class ImplementationReasoningResponse(BaseModel):
     claim: CustomerImplementationClaim
-    assessments: List[ImplementationAssessment] = Field(default_factory=list)
+    mappings: List[ClaimObligationMapping] = Field(default_factory=list)
     missing_evidence: List[str] = Field(default_factory=list)
     summary: str = ""
+    # Makes the Welt-1 boundary explicit: this is advisory claim-mapping, not a
+    # conformity verdict (that is ComplianceStatus in the Execution Graph).
+    disclaimer: str = ""
 
 
 class InterpretationRequest(BaseModel):