knowledge: rewrite RAGcoreKnowledgeProvider to the real search/answers contract

The previous adapter targeted an endpoint shape RAGcore never actually
exposed. health() now checks /health/ready and ask() posts to the real
POST /v1/answers with Bearer auth and requested_space_ids, matching
RAGcore's actual contract after this session's Bearer-auth and
search/answer wiring work.

Adds RAGCORE_SPACE_ID config/env plumbing (a question is meaningless
without a knowledge space to scope it to) and 12 new adapter tests
covering degradation paths: missing space id, connection errors,
non-200 responses, malformed responses, not-answerable, and
answerable-without-citations all fail closed to "insufficient
evidence" rather than fabricating an answer.

KNOWLEDGE_PROVIDER stays "demo" in production for now -- switching
requires RAGcore's own search/answer application to actually be
deployed and live-verified, tracked separately in PROJECT_STATE.md.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/tests/test_knowledge.py

@@ -158,12 +158,190 @@ def test_knowledge_status_endpoint(ops_client):
     assert response.json()["provider"] == "demo"
 
 
-def test_ragcore_provider_degrades_to_unavailable(monkeypatch):
-    def fake_client(*args, **kwargs):
-        raise httpx.ConnectError("no ragcore in this environment")
+class _FakeResponse:
+    def __init__(self, status_code: int, body: dict):
+        self.status_code = status_code
+        self._body = body
 
+    def json(self) -> dict:
+        return self._body
+
+
+class _FakeClient:
+    def __init__(self, get_response=None, post_response=None, raise_on=None):
+        self._get_response = get_response
+        self._post_response = post_response
+        self._raise_on = raise_on
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *args):
+        return False
+
+    def get(self, path):
+        if self._raise_on == "get":
+            raise httpx.ConnectError("no ragcore in this environment")
+        return self._get_response
+
+    def post(self, path, json=None):
+        if self._raise_on == "post":
+            raise httpx.ConnectError("no ragcore in this environment")
+        return self._post_response
+
+
+def test_ragcore_provider_degrades_to_unavailable(monkeypatch):
     provider = RAGcoreKnowledgeProvider()
-    monkeypatch.setattr(provider, "_client", fake_client)
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(provider, "_client", lambda: _FakeClient(raise_on="post"))
     answer = provider.ask("Anything?", "test-correlation-3")
     assert answer.evidence_state == "unavailable"
     assert answer.sources == []
+
+
+def test_ragcore_provider_without_configured_space_is_unavailable_without_a_network_call(
+    monkeypatch,
+):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "")
+
+    def fail_if_called():
+        raise AssertionError("should not call RAGcore without a configured space id")
+
+    monkeypatch.setattr(provider, "_client", fail_if_called)
+    answer = provider.ask("Anything?", "test-correlation-no-space")
+    assert answer.evidence_state == "unavailable"
+
+
+def test_ragcore_provider_health_reports_ready_status(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(get_response=_FakeResponse(200, {"status": "ok"})),
+    )
+    health = provider.health()
+    assert health.provider == "ragcore"
+    assert health.available is True
+
+
+def test_ragcore_provider_health_reports_degraded_status(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(get_response=_FakeResponse(200, {"status": "degraded"})),
+    )
+    health = provider.health()
+    assert health.available is False
+
+
+def test_ragcore_provider_health_degrades_on_connection_error(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider, "_client", lambda: _FakeClient(raise_on="get"))
+    health = provider.health()
+    assert health.available is False
+    assert "unavailable" in health.detail.lower()
+
+
+def _answers_body(**overrides) -> dict:
+    body = {
+        "answer": "Report damage and route the vehicle to maintenance.",
+        "answerability": "answerable",
+        "citations": [
+            {
+                "id": "cite-1",
+                "document_id": "doc-1",
+                "document_version_id": "version-1",
+                "title": "Damage handling procedure",
+                "section": "Detection",
+                "excerpt": "Inspect the vehicle for visible damage.",
+            }
+        ],
+    }
+    body.update(overrides)
+    return body
+
+
+def test_ragcore_provider_grounded_answer_maps_citations_to_sources(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(post_response=_FakeResponse(200, _answers_body())),
+    )
+    answer = provider.ask("What must I do about damage?", "test-correlation-grounded")
+    assert answer.evidence_state == "grounded"
+    assert answer.answer
+    assert len(answer.sources) == 1
+    source = answer.sources[0]
+    assert source.document_id == "doc-1"
+    assert source.title == "Damage handling procedure"
+    assert source.version == "version-1"
+    assert source.section == "Detection"
+    assert source.excerpt
+
+
+def test_ragcore_provider_not_answerable_is_insufficient_and_never_fabricates(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(
+            post_response=_FakeResponse(
+                200,
+                _answers_body(
+                    answer="This should never be shown.",
+                    answerability="not_answerable",
+                    citations=[],
+                ),
+            )
+        ),
+    )
+    answer = provider.ask("Unrelated question?", "test-correlation-insufficient")
+    assert answer.evidence_state == "insufficient"
+    assert answer.answer == ""
+    assert answer.sources == []
+
+
+def test_ragcore_provider_answerable_without_citations_is_insufficient(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(
+            post_response=_FakeResponse(
+                200, _answers_body(answerability="answerable", citations=[])
+            )
+        ),
+    )
+    answer = provider.ask("What must I do about damage?", "test-correlation-no-citations")
+    assert answer.evidence_state == "insufficient"
+    assert answer.sources == []
+
+
+def test_ragcore_provider_non_200_response_is_unavailable(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(post_response=_FakeResponse(401, {"code": "AUTHENTICATION_REQUIRED"})),
+    )
+    answer = provider.ask("Anything?", "test-correlation-401")
+    assert answer.evidence_state == "unavailable"
+
+
+def test_ragcore_provider_malformed_response_is_unavailable(monkeypatch):
+    provider = RAGcoreKnowledgeProvider()
+    monkeypatch.setattr(provider._settings, "ragcore_space_id", "space-1")
+    monkeypatch.setattr(
+        provider,
+        "_client",
+        lambda: _FakeClient(post_response=_FakeResponse(200, {"citations": "not-a-list"})),
+    )
+    answer = provider.ask("Anything?", "test-correlation-malformed")
+    assert answer.evidence_state == "unavailable"