fix(ci): stop ui_unit_tests vitest onTaskUpdate RPC timeout flake

The ui_unit_tests job runs vitest with maxForks=8 on an 8-vCPU xlarge
container, leaving no headroom for the main vitest process that services
worker RPCs. Under full CPU saturation the coordinator misses the
onTaskUpdate ack, vitest raises "Timeout calling onTaskUpdate" as an
unhandled error, and the job exits 1 even though every test passes.

Lower maxForks to 6 so the coordinator, jsdom, and OS keep two cores, and
raise teardownTimeout to 60s for extra slack on heavy runs.

.circleci/config.yml

@@ -2629,7 +2629,7 @@ jobs:
             cd ui/litellm-dashboard
 
             CI=true npm run test -- --run \
-              --pool forks --poolOptions.forks.maxForks=8
+              --pool forks --poolOptions.forks.maxForks=6
 
   e2e_ui_testing:
     docker:

ui/litellm-dashboard/vitest.config.ts

@@ -8,6 +8,7 @@ export default defineConfig({
     globals: true,
     css: true, // lets you import CSS/modules without extra mocks
     testTimeout: 30000,
+    teardownTimeout: 60000,
     coverage: {
       provider: "v8",
       reporter: ["text", "lcov"],