feat: complete catalog-driven preprocessing

backend/test/workspaces/evidence/preprocessing.test.ts

@@ -138,6 +138,30 @@ test("projects aggregate no-Evidence and completed-stage outcomes without rerunn
   expect(deps.persistJob).not.toHaveBeenCalled();
 });
 
+test("complete preprocessing preflights BM25 before continuing with Evidence", async () => {
+  const deps = dependencies();
+  deps.evidencePreflight.mockResolvedValue({
+    ok: false as const,
+    code: "semantic_index_incompatible" as const,
+  });
+  const state = job({ completedStages: ["catalog_snapshot", "schema_index"] });
+
+  const result = await continueEvidencePreprocessing(
+    { evidence: filesystemEvidence, job: state },
+    deps,
+  );
+
+  expect(deps.evidencePreflight).toHaveBeenCalledOnce();
+  expect(deps.runStage).not.toHaveBeenCalled();
+  expect(result).toEqual({
+    status: "failed",
+    code: "semantic_index_incompatible",
+    runId: "a".repeat(32),
+    childRuns: {},
+    completedStages: ["catalog_snapshot", "schema_index"],
+  });
+});
+
 test("preserves the narrow standalone projection for an already completed Evidence stage", async () => {
   const deps = dependencies();