Add configurable Public Workspace display name

[Paul Lizer (paullizer)]

Summary

• Add a 32-character Admin Settings field for the end-user Public Workspace display name.
• Use sanitized label context across end-user navigation, Profile, Public Directory, Public Workspace pages, chat scope labels, and related browser messages.
• Keep admin/internal terminology, APIs, routes, roles, storage fields, and identifiers as Public Workspace/public_workspace.
• Add feature documentation, release notes, and regression coverage.

Fixes #1146

Validation

• python functional_tests\test_public_workspace_display_name_settings.py
• python -m py_compile application\single_app\functions_settings.py application\single_app\route_frontend_admin_settings.py functional_tests\test_public_workspace_display_name_settings.py ui_tests\test_public_workspace_display_name_ui.py
• node --check for changed JavaScript files
• python -m pytest ui_tests\test_public_workspace_display_name_ui.py -q (skips without UI env/storage state)
• git diff --check