[Docs] Java SDK Generation Pipeline Touble Shooting Guide

[JackTn]

This pull request adds a comprehensive troubleshooting guide for the Java SDK generation pipeline according to https://github.com/Azure/azure-sdk-pr/issues/2481#issuecomment-3821506654 . The guide helps engineers quickly identify the category of pipeline failures and provides actionable solutions, including real-world examples and quick reference tables. The documentation is organized to cover common error types, customization issues, intermittent failures, and escalation steps.

Java SDK generation pipeline troubleshooting documentation:

Pipeline configuration errors

• Added detailed instructions for resolving tspconfig.yaml misconfigurations, including missing or invalid namespace, incorrect emitter-output-dir, and cases where no SDK folder is found.

Customization conflicts

• Provided guidance for fixing compilation errors caused by hand-written customization code, including incompatible customizations, missing or merged members, and duplicate/ambiguous operations. Includes prerequisites for customization and real-world examples.

Intermittent infrastructure failures

• Documented solutions for transient errors such as Maven dependency download failures, npm installation issues, git operation failures, and CI infrastructure problems, with advice to re-run the pipeline and escalation steps if issues persist.

Quick reference and escalation

• Added a quick reference table mapping common error patterns to their categories and solutions, and included instructions for escalating persistent issues to the Java Teams channel with required information.

Related resources and links

• Linked to relevant FAQs, pipeline documentation, SDK support channels, and real-world troubleshooting

[srnagar]

Fix typo in PR title.