feat: harden runtime readiness and session workflow

harness/tests/test_search_pack.py

@@ -7,6 +7,7 @@ from typer.testing import CliRunner
 from tht.cli import app
 from tht.config import load_config
 from tht.jobs.dwh_pipeline import DwhPreprocessPipeline, config_dwh_binding
+from tht.ports.vector import VectorReadUnavailable
 from tht.mschema.models import ColumnPhysical, PhysicalSchema, TablePhysical
 from tht.vectorstore.embeddings import EmbeddingsError
 
@@ -116,6 +117,21 @@ def test_pack_json_and_session_file(tmp_path, monkeypatch):
     assert "Retrieval pack" in pack.read_text()
 
 
+def test_pack_degrades_direct_vector_read_error(tmp_path, monkeypatch):
+    cfg = _workspace(tmp_path)
+
+    class _BrokenSearcher:
+        def search(self, vec, top_n, kinds=None):
+            raise VectorReadUnavailable("Vector read operation unavailable")
+
+    _patch(monkeypatch, _FakeEmbedder(), _BrokenSearcher())
+    res = CliRunner().invoke(app, ["search", "pack", "q", "-c", str(cfg), "--json"])
+    assert res.exit_code == 0, res.output
+    data = json.loads(res.output[res.output.index("{"):])
+    assert data["tables"] == [] and data["evidence"] == [] and data["solved"] == []
+    assert len(data["warnings"]) == 2
+
+
 def test_pack_degrades_gracefully(tmp_path, monkeypatch):
     cfg = _workspace(tmp_path)