dsh-plugin-java-engineer: DeepSeek Harness Java Engineer Toolbox

The DSH plugin maintained by flynow-harness is an MIT-licensed project compatible with dsh@0.2.2-alpha.2. It provides 6 deterministic Host tools: java_env_probe (environment health check), java_project_audit (build audit), java_scaffold_spring_boot (scaffolding), java_jvm_tune (JVM tuning), java_review_file (code review), and java_snippet (snippet library), along with a Web input toolbar. All tools are read-only or pure computation except for scaffolding. Installation requires cloning the repository via `git clone` and passing the absolute repository path to `plugin_manager install_bundle`. Uninstallation is performed using `remove_bundle @local/java-engineer`.