Add support for custom tls server names.

[brendandburns]

Add the ability to set the tls-server name to be different than the host name.

See kubernetes-client/java#3241 for the user request.

cc
@bbdouglas @sreeshas @jfiala @lukoyanov @cbornet @jeff9finger @karismann @Zomzog @lwlee2608 @martin-mfg
for Java

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[wing328]

Error:  COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[309,15] error: cannot find symbol
  symbol:   variable tlsServerName
  location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[321,12] error: cannot find symbol
  symbol: variable tlsServerName
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1565,20] error: cannot find symbol
  symbol:   variable tlsServerName
  location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1565,46] error: cannot find symbol
  symbol:   variable tlsServerName
  location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1570,70] error: cannot find symbol
  symbol: variable tlsServerName
[INFO] 5 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  12.035 s
[INFO] Finished at: 2025-11-18T00:53:37Z
[INFO] ------------------------------------------------------------------------
[INFO] 5 goals, 5 executed
Error:  Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project openapi-java-client: Compilation failure: Compilation failure: 
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[309,15] error: cannot find symbol
Error:    symbol:   variable tlsServerName
Error:    location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[321,12] error: cannot find symbol
Error:    symbol: variable tlsServerName
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1565,20] error: cannot find symbol
Error:    symbol:   variable tlsServerName
Error:    location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1565,46] error: cannot find symbol
Error:    symbol:   variable tlsServerName
Error:    location: class ApiClient
Error:  /home/runner/work/openapi-generator/openapi-generator/samples/client/others/java/okhttp-gson-oneOf/src/main/java/org/openapitools/client/ApiClient.java:[1570,70] error: cannot find symbol
Error:    symbol: variable tlsServerName
Error:  -> [Help 1]
Error:  
Error:  To see the full stack trace of the errors, re-run Maven with the -e switch.
Error:  Re-run Maven using the -X switch to enable full debug logging.

thanks for the PR. can you please review the CI build failure when you've time?

[brendandburns]

Sorry, I cut and pasted this from my client library and I missed that variable declaration (embarrassing!)

Now fixed, please take another look!

[wing328]

No problem. I'll review and try to get it merged by the end of this week.