fix: correct span naming to match Python implementation

- Change span names from {model}.completion to {model}
- bedrock.chat.completion -> bedrock.chat
- Matches Python callback handler naming convention
- Update test to expect correct span names
- All tests passing

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: nirga

packages/instrumentation-langchain/src/callback_handler.ts

@@ -61,7 +61,7 @@ export class TraceloopCallbackHandler extends BaseCallbackHandler {
     const spanBaseName = this.convertClassNameToSpanName(className);
 
     // Create single LLM span like Python implementation
-    const span = this.tracer.startSpan(`${spanBaseName}.completion`, {
+    const span = this.tracer.startSpan(spanBaseName, {
       kind: SpanKind.CLIENT,
     });
 
@@ -105,7 +105,7 @@ export class TraceloopCallbackHandler extends BaseCallbackHandler {
     const spanBaseName = this.convertClassNameToSpanName(className);
 
     // Create single LLM span like handleChatModelStart
-    const span = this.tracer.startSpan(`${spanBaseName}.completion`, {
+    const span = this.tracer.startSpan(spanBaseName, {
       kind: SpanKind.CLIENT,
     });
 

packages/instrumentation-langchain/test/instrumentation.test.ts

@@ -461,9 +461,9 @@ describe("Test Langchain instrumentation", async function () {
       assert.ok(attributes[SpanAttributes.LLM_USAGE_COMPLETION_TOKENS]);
       assert.ok(attributes[SpanAttributes.LLM_USAGE_TOTAL_TOKENS]);
     } else {
-      // Test LangChain callback handler spans - now only creates completion span
+      // Test LangChain callback handler spans - now only creates completion span  
       const completionSpan = spans.find(
-        (span) => span.name === "bedrock.chat.completion",
+        (span) => span.name === "bedrock.chat",
       );
 
       assert.ok(