Mark recall-limited obligations in DSE shadow telemetry

Trennt im Shadow drei Kategorien statt eines pauschalen FAILED:
  - echte Lücke (failed_by_current_checker)
  - redundanter Control-FP (kollabiert per OR zu MET)
  - Prüfer-Reichweitenproblem (recall_limited)

obligation_taxonomy.py: decision_method_required=LLM für recipients_disclosed,
third_country_transfer_disclosed, safeguards_disclosed, safeguards_accessible
(versioniertes Registry-Artefakt bis DB-Tabelle, v1-Spec). Empirisch: TeamViewer
0/22 kw+emb trotz erfüllter Pflicht (cos 0.49-0.57) → CONTENT/LLM-Klasse, kein Schwellen-Fix.

compute_obligation_shadow segregiert FAILED/PARTIAL über requires_llm(): teamviewer
5 Findings → 2 echte + 3 recall_limited. 9 neue Unit-Tests (41 gesamt grün).

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

backend-compliance/tests/test_obligation_taxonomy.py

@@ -0,0 +1,20 @@
+"""Unit-Tests für die Obligation-Taxonomie-Registry (decision_method_required)."""
+from compliance.services.obligation_taxonomy import OBLIGATION_META, requires_llm
+
+
+class TestRequiresLlm:
+    def test_marked_obligations_require_llm(self):
+        for ob in ("recipients_disclosed", "third_country_transfer_disclosed",
+                   "safeguards_disclosed", "safeguards_accessible"):
+            assert requires_llm(ob) is True
+
+    def test_unmarked_obligation_does_not(self):
+        assert requires_llm("art20_right_exists_core") is False
+        assert requires_llm("objection_general_art21_1") is False
+
+    def test_unknown_obligation_is_false(self):
+        assert requires_llm("does_not_exist") is False
+
+    def test_registry_values_are_llm(self):
+        assert all(v.get("decision_method_required") == "LLM"
+                   for v in OBLIGATION_META.values())