Fix issue with Ollama usage not being tracked and shown in 9router UI (#1102)

Co-authored-by: Abhi <abhi@fresent.com>

open-sse/utils/usageTracking.js

@@ -220,6 +220,16 @@ export function extractUsage(chunk) {
     });
   }
 
+  // Ollama NDJSON format (raw from provider, before translation)
+  // Ollama sends: {"model":"...","done":true,"prompt_eval_count":N,"eval_count":M}
+  if (chunk.done === true && typeof chunk.prompt_eval_count === "number") {
+    return normalizeUsage({
+      prompt_tokens: chunk.prompt_eval_count || 0,
+      completion_tokens: chunk.eval_count || 0,
+      total_tokens: (chunk.prompt_eval_count || 0) + (chunk.eval_count || 0)
+    });
+  }
+
   return null;
 }