Add obligation discovery pipeline tooling

Sichert die validierte Obligation Discovery Pipeline aus /tmp als dauerhaftes,
committetes Tooling (scripts/obligation_discovery/) — der eigentliche Vermögenswert.

Stufen: precluster (Embedding-Cache + Mikro-Cluster) → meta_cluster (Review Units,
Skalierungs-Fix) → synthesize_obligations (Opus, Key aus ENV, Streaming, harte Tier-Regel,
Provenance) → validate_registry → merge_review_diff. Reine Helfer in _core.py, 16 Unit-Tests.

Doku docs-src/development/obligation_discovery_pipeline_v1.md mit Meilensteinen
(SBOM/Vuln reproduziert, Auth 4408→170 Review Units→54→kuriert 29) und der Architekturregel:
Runtime deterministisch, Discovery LLM-gestützt.

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

scripts/obligation_discovery/_core.py

@@ -0,0 +1,114 @@
+"""Reine Helfer der Obligation Discovery Pipeline (keine schweren Imports → unit-testbar).
+
+Die Pipeline leitet aus großen Compliance-Korpora eine regulatorische Ontologie ab:
+  Controls → Mikro-Cluster → Meta-Cluster/Review-Units → LLM-Synthese → Obligation Registry.
+Architekturregel: RUNTIME bleibt deterministisch; DISCOVERY (dieses Tooling) darf LLM-gestützt
+sein und läuft EINMALIG/offline. Siehe docs-src/development/obligation_discovery_pipeline_v1.md.
+"""
+from __future__ import annotations
+
+import ast
+import json
+import math
+from typing import Optional
+
+SEMANTIC_EDGE_TYPES = ("depends_on", "supports", "produces_evidence_for",
+                       "implements", "derived_from")
+
+
+def parse_req(req) -> list:
+    """requirements-Spalte (JSON ODER Python-Repr ODER String) robust zu Liste."""
+    if isinstance(req, list):
+        return req
+    if isinstance(req, str):
+        for fn in (json.loads, ast.literal_eval):
+            try:
+                v = fn(req)
+                return v if isinstance(v, list) else [str(v)]
+            except Exception:
+                pass
+        return [req]
+    return []
+
+
+def cosine(a, b) -> float:
+    if not a or not b:
+        return 0.0
+    dot = sum(x * y for x, y in zip(a, b))
+    na = math.sqrt(sum(x * x for x in a))
+    nb = math.sqrt(sum(y * y for y in b))
+    return dot / (na * nb) if na and nb else 0.0
+
+
+def greedy_cluster(vecs: list, thr: float) -> list[dict]:
+    """Single-Pass-Greedy-Clustering: jeder Vektor joint den ersten Cluster, dessen Seed
+    cosine ≥ thr ist, sonst neuer Cluster. Deterministisch (stabile Reihenfolge)."""
+    clusters: list[dict] = []
+    for i, v in enumerate(vecs):
+        if not v:
+            clusters.append({"seed": None, "members": [i]})
+            continue
+        best, best_sim = None, thr
+        for c in clusters:
+            if c["seed"] is None:
+                continue
+            s = cosine(v, c["seed"])
+            if s >= best_sim:
+                best_sim, best = s, c
+        if best:
+            best["members"].append(i)
+        else:
+            clusters.append({"seed": v, "members": [i]})
+    return clusters
+
+
+def centroid(idxs: list[int], vecs: list) -> Optional[list]:
+    vs = [vecs[i] for i in idxs if vecs[i]]
+    if not vs:
+        return None
+    n = len(vs)
+    return [sum(col) / n for col in zip(*vs)]
+
+
+def validate_registry(reg: dict) -> dict:
+    """Belastbarkeits-Checks (User-Regeln): LEGAL_MINIMUM braucht legal_basis,
+    member_controls vollständig, out_of_scope separat, >8-Obligations/Review-Unit-Warnung."""
+    obls = reg.get("obligations", [])
+    lm = [o for o in obls if o.get("tier") == "LEGAL_MINIMUM"]
+    lm_without_basis = [o["id"] for o in lm if not o.get("legal_basis")]
+    empty_members = [o["id"] for o in obls if not o.get("member_controls")]
+    per_unit: dict[str, int] = {}
+    for o in obls:
+        ru = (o.get("provenance") or {}).get("source_meta_cluster")
+        if ru:
+            per_unit[ru] = per_unit.get(ru, 0) + 1
+    over8 = {ru: n for ru, n in per_unit.items() if n > 8}
+    rels = reg.get("relationships", [])
+    return {
+        "obligations": len(obls),
+        "legal_minimum": len(lm),
+        "lm_without_legal_basis": lm_without_basis,
+        "empty_member_controls": empty_members,
+        "over8_per_review_unit": over8,
+        "out_of_scope": sum(1 for r in rels if r.get("type") == "out_of_scope"),
+        "semantic_edges": sum(1 for r in rels if r.get("type") in SEMANTIC_EDGE_TYPES),
+        "passed": not lm_without_basis and not empty_members and not over8,
+    }
+
+
+def merge_edges(relationships: list[dict], proposed: list[dict]) -> tuple[list[dict], int]:
+    """Proposed semantische Kanten dedupliziert in relationships mergen. Gibt (merged, added)."""
+    existing = {(r.get("type"), r.get("from"), r.get("to"))
+                for r in relationships if r.get("from")}
+    added = 0
+    out = list(relationships)
+    for e in proposed:
+        if e.get("type") not in SEMANTIC_EDGE_TYPES:
+            continue
+        key = (e["type"], e.get("from"), e.get("to"))
+        if key in existing or not e.get("from") or not e.get("to"):
+            continue
+        out.append(e)
+        existing.add(key)
+        added += 1
+    return out, added