Add Java @clientName renames for Operations and SubNamespace in multiple-services spec (#4221)

- [x] Add `@clientName` Java renames for Operations and SubNamespace in
multiple-services spec
- [x] Add changelog entry via `.chronus/changes/`

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: weidongxu-microsoft <53292327+weidongxu-microsoft@users.noreply.github.com>

Author: Copilot

.chronus/changes/multiple-services-java-clientname-2026-4-9-6-3-25.md

@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: feature
+packages:
+  - "@azure-tools/azure-http-specs"
+---
+
+Add `@clientName` Java-scoped renames for `Operations` and `SubNamespace` in the multiple-services spec to avoid name collisions in Java codegen.

packages/azure-http-specs/specs/service/multiple-services/main.tsp

@@ -1,10 +1,12 @@
 import "@typespec/versioning";
 import "@typespec/http";
 import "@typespec/spector";
+import "@azure-tools/typespec-client-generator-core";
 
 using Versioning;
 using Http;
 using Spector;
+using Azure.ClientGenerator.Core;
 
 namespace Service.MultipleServices;
 
@@ -20,6 +22,7 @@ namespace ServiceA {
     av2,
   }
 
+  @clientName("AOperations", "java")
   interface Operations {
     @scenario
     @scenarioDoc("""
@@ -34,6 +37,7 @@ namespace ServiceA {
     opA(@query("api-version") apiVersion: VersionsA): void;
   }
 
+  @clientName("ASubNamespace", "java")
   namespace SubNamespace {
     @scenario
     @scenarioDoc("""
@@ -61,6 +65,7 @@ namespace ServiceB {
     bv2,
   }
 
+  @clientName("BOperations", "java")
   interface Operations {
     @scenario
     @scenarioDoc("""
@@ -75,6 +80,7 @@ namespace ServiceB {
     opB(@query("api-version") apiVersion: VersionsB): void;
   }
 
+  @clientName("BSubNamespace", "java")
   namespace SubNamespace {
     @scenario
     @scenarioDoc("""