fix(preprocess): reconcile durable DWH generations

harness/tests/test_lsh_job_resume.py

@@ -100,6 +100,7 @@ def test_resume_rejects_tampered_succeeded_stage_artifact(tmp_path):
 
 def test_post_publish_crash_reconciles_same_generation_on_resume(tmp_path):
     crashed = False
+    builder_calls = 0
 
     def crash_once(_generation):
         nonlocal crashed
@@ -107,11 +108,16 @@ def test_post_publish_crash_reconciles_same_generation_on_resume(tmp_path):
             crashed = True
             raise KeyboardInterrupt("simulated process death")
 
+    def build(physical, output):
+        nonlocal builder_calls
+        builder_calls += 1
+        _recover_lsh([], output)
+
     pipeline = DwhPreprocessPipeline(
         workspace_id="demo", workspace_root=tmp_path,
         config_fingerprint=FP, input_fingerprint=FP,
         introspect=lambda output: output.write_text("catalog"),
-        build_lsh=lambda physical, output: _recover_lsh([], output),
+        build_lsh=build,
         after_publish=crash_once,
     )
     with pytest.raises(KeyboardInterrupt):
@@ -123,7 +129,8 @@ def test_post_publish_crash_reconciles_same_generation_on_resume(tmp_path):
 
     resumed = pipeline.run(("introspect", "lsh"), resume_run_id=source_run_id)
     assert resumed.status == "succeeded"
-    assert (tmp_path / ".tht-dwh" / "ACTIVE").read_text().strip() == resumed.run_id
+    assert builder_calls == 1
+    assert (tmp_path / ".tht-dwh" / "ACTIVE").read_text().strip() == source_run_id
 
 
 def test_resume_of_succeeded_run_detects_tampered_published_file(tmp_path):
@@ -137,7 +144,8 @@ def test_resume_of_succeeded_run_detects_tampered_published_file(tmp_path):
     published = (
         tmp_path / ".tht-dwh" / "generations" / succeeded.run_id / "demo_meta.json"
     )
+    published.chmod(0o600)
     published.write_text("tampered")
 
-    with pytest.raises(Exception, match="digest mismatch"):
+    with pytest.raises(Exception, match="published DWH"):
         pipeline.run(("introspect", "lsh"), resume_run_id=succeeded.run_id)