fix(merge): restore ANTHROPIC_COMPATIBLE_PREFIX import + drop dead appendRequestLog call

Full-source eslint no-undef sweep over src/ + open-sse/ (config
listing node/web globals) found two remaining undeclared-variable
regressions of the same merge-loss family:

* api/providers/test-batch: branch commit f0adfb20 added a
  providerId.startsWith(ANTHROPIC_COMPATIBLE_PREFIX) check but never
  imported it; the master merge kept the buggy line. Every batch
  test / provider-group filter touching a non-openai-compatible
  provider threw ReferenceError (|| does not short-circuit).
* utils/stream.js finalizeStream: no-usage fallback called
  appendRequestLog(), a stub upstream had marked no-op and whose
  export chain was dropped by the merge. The call site only fires
  when a stream ends without valid usage and now threw
  ReferenceError inside the terminal callback. Removed the dead
  call (behaviour identical: the stub wrote nothing).

All other no-undef reports are browser globals absent from the
scan config, not source bugs. next build --webpack passes; smoke
server boots and auth-rejects unauthenticated /v1 + /api traffic
as expected; unit suite 1746 pass / 103 fail (was 1738/111).

open-sse/utils/stream.js

@@ -98,9 +98,10 @@ export function createSSEStream(options = {}) {
 
     if (hasValidUsage(finalUsage)) {
       logUsage(isPassthrough ? provider : (state?.provider || targetFormat), finalUsage, model, connectionId, apiKey);
-    } else {
-      appendRequestLog({ model, provider, connectionId, tokens: null, status: "200 OK" }).catch(() => { });
     }
+    // No else branch: the old appendRequestLog() fallback was a no-op stub
+    // (request log is derived from usageHistory on read) and was dropped by
+    // the master merge; logging a 200 with tokens:null was a cosmetic entry.
 
     if (onStreamComplete) {
       onStreamComplete({

src/app/api/providers/test-batch/route.js

@@ -6,6 +6,7 @@ import {
   OAUTH_PROVIDERS,
   APIKEY_PROVIDERS,
   OPENAI_COMPATIBLE_PREFIX,
+  ANTHROPIC_COMPATIBLE_PREFIX,
 } from "@/shared/constants/providers";
 import { testSingleConnection } from "../[id]/test/testUtils.js";