feat: #5b materialize capability layer (Modell C) — capabilities.json + cra_core.json

User-Entscheidung Modell C + objective_tags-Safeguard (Tags, keine Klasse). Deterministisch
via materialize_capabilities.py:
- obligations/capabilities.json: 5 Capabilities (multi_factor_authentication/session_management/
  transport_encryption/code_signing/security_monitoring_alerting), realized_by (n:m) +
  guidance_basis KANONISCH hochgezogen. access_control gedroppt (OVERLAP).
- obligations/cra_core.json: 2 CORE-Sicherheitsziele (attack_surface_minimization (2)(j)/CM-7 +
  software_integrity_protection (2)(f)/SI-7) -> fuellt den #4-NIST-Gap.
- DOMAIN specializes->CORE (remote_access_attack_surface_min, component_remote_interface_security,
  signed_update_integrity, firmware_software_authentication) + objective_tags.
- Merge: vuln_remediation_patching -> deprecated_alias von provide_security_updates.
- remote_access_data_export_protection bleibt BEST_PRACTICE (pending Data-Act-Scope).
- join_keys 93->95 (core 2). Bidirektional validiert.

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

obligations/obligation_join_keys.json

@@ -1,7 +1,7 @@
 {
  "schema_version": "obligation_join_keys_v1",
  "contract": "obligation_id ist der stabile Join-Key. Legal Knowledge Graph haengt citation_spans an obligation_id; Compliance Execution Graph mappt control_mapping.source_norm -> obligation_id. Interim-Bruecke = citation_units. obligation_id NIE neu vergeben (re-link).",
- "count": 93,
+ "count": 95,
  "obligation_ids": [
   {
    "obligation_id": "sbom_creation",
@@ -175,6 +175,26 @@
    ],
    "source_role": "LEGAL_BASIS"
   },
+  {
+   "obligation_id": "attack_surface_minimization",
+   "regulation": "CRA",
+   "family": "core",
+   "tier": "LEGAL_MINIMUM",
+   "citation_units": [
+    "Annex I Part I (2)(j)"
+   ],
+   "source_role": "LEGAL_BASIS"
+  },
+  {
+   "obligation_id": "software_integrity_protection",
+   "regulation": "CRA",
+   "family": "core",
+   "tier": "LEGAL_MINIMUM",
+   "citation_units": [
+    "Annex I Part I (2)(f)"
+   ],
+   "source_role": "LEGAL_BASIS"
+  },
   {
    "obligation_id": "user_authentication_required",
    "regulation": "CRA",