feat(impressum): Snapshot-Modul-Tab — ImpressumAgent auf gespeichertem Text

Snapshot-Detailseite wird zu Modul-Tabs (Cookies & Tracking | Impressum).
Backend GET /snapshots/{id}/impressum-check laeuft den v3 ImpressumAgent auf
dem gespeicherten Impressum-Text (kein Re-Crawl); Input-Erzeugung in
impressum_input_from_snapshot() ausgelagert (pure + getestet: Text/Scope/
company_name-Fallback/None-Pfad). Frontend laedt lazy beim Tab-Wechsel und
rendert mit dem bestehenden AgentResultTab (keine zweite Engine).

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

backend-compliance/compliance/tests/test_impressum_snapshot_input.py

@@ -0,0 +1,47 @@
+"""impressum_input_from_snapshot — Snapshot → ImpressumAgent-Input (pure).
+
+Deckt die Glue des /snapshots/{id}/impressum-check-Endpoints ohne DB/LLM ab:
+Text-Extraktion, Scope-Ableitung (Profil), company_name-Fallback, None-Pfad.
+"""
+
+from __future__ import annotations
+
+from compliance.api.agent_check._agent_outputs import (
+    impressum_input_from_snapshot,
+)
+
+
+def _snap(text: str = "x" * 200, **over) -> dict:
+    s = {
+        "doc_entries": [{"doc_type": "impressum", "text": text}],
+        "profile": {}, "scan_context": None,
+        "site_label": "BMW", "site_domain": "bmw.de",
+    }
+    s.update(over)
+    return s
+
+
+def test_builds_input_from_impressum_text():
+    inp = impressum_input_from_snapshot(_snap())
+    assert inp is not None
+    assert inp["doc_type"] == "impressum"
+    assert inp["text"].startswith("x")
+    assert inp["company_name"] == "BMW"          # site_label-Fallback
+    assert inp["origin_domain"] == "bmw.de"
+    assert isinstance(inp["business_scope"], list)
+
+
+def test_none_when_no_or_short_impressum_text():
+    assert impressum_input_from_snapshot(_snap(doc_entries=[])) is None
+    assert impressum_input_from_snapshot(
+        {"doc_entries": [{"doc_type": "impressum", "text": "zu kurz"}]}) is None
+
+
+def test_scope_includes_profile_derived():
+    inp = impressum_input_from_snapshot(_snap(profile={"has_online_shop": True}))
+    assert "ecommerce" in inp["business_scope"]
+
+
+def test_company_name_prefers_profile_over_site_label():
+    inp = impressum_input_from_snapshot(_snap(profile={"company_name": "ACME AG"}))
+    assert inp["company_name"] == "ACME AG"