feat(evidence): use server-side Qdrant BM25 retrieval

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

@@ -39,13 +39,11 @@ function job(overrides: Partial<EvidenceJobState> = {}): EvidenceJobState {
 function dependencies(payload: Record<string, unknown> = {}): EvidencePreprocessingDependencies & {
   runStage: ReturnType<typeof vi.fn>;
   persistJob: ReturnType<typeof vi.fn>;
-  semanticPreflight: ReturnType<typeof vi.fn>;
   evidencePreflight: ReturnType<typeof vi.fn>;
 } {
   return {
     runStage: vi.fn(async () => payload),
     persistJob: vi.fn(),
-    semanticPreflight: vi.fn(async () => ({ ok: true as const })),
     evidencePreflight: vi.fn(async () => ({ ok: true as const })),
     requireRunId(value) {
       if (typeof value !== "string" || !/^[0-9a-f]{32}$/.test(value)) {
@@ -72,7 +70,6 @@ test("Evidence maintenance preflights the additive BM25 contract before starting
   );
 
   expect(deps.evidencePreflight).toHaveBeenCalledOnce();
-  expect(deps.semanticPreflight).not.toHaveBeenCalled();
   expect(deps.runStage).toHaveBeenCalledWith([
     "preprocess", "evidence", "--resume", "b".repeat(32), "--json", "-c", "/dev/fd/3",
   ]);
@@ -104,7 +101,6 @@ test("owns Evidence egress refusal before shared semantic infrastructure", async
   );
 
   expect(result).toEqual({ status: "failed", code: "egress_policy_refused" });
-  expect(deps.semanticPreflight).not.toHaveBeenCalled();
   expect(deps.runStage).not.toHaveBeenCalled();
   expect(deps.persistJob).not.toHaveBeenCalled();
 });