Add document-review UIWorker example

Synthesis example: a ReplyToolMixin UIWorker adds a start_review tool that fans
out to clarity/tone peers via start_user_job_group, translates each reviewer
response into an add_note command in on_job_response, handles a client
note_click event via @on_ui_event, and keeps history across turns.

examples/multi-worker/ui-worker/document-review/client/.gitignore

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+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+pnpm-debug.log*
+lerna-debug.log*
+
+node_modules
+dist
+dist-ssr
+*.local
+
+# Editor directories and files
+.vscode/*
+!.vscode/extensions.json
+.idea
+.DS_Store
+*.suo
+*.ntvs*
+*.njsproj
+*.sln
+*.sw?
+
+.vite