feat(ui): hide status bar by default

[nmrtist]

Summary

• hide the bottom status bar by default to increase workspace space
• add a persistent Show status bar preference under Appearance
• expose the preference through the property catalog and searchable settings
• update the English and Simplified Chinese documentation
• add coverage for defaults, persistence, preference reset, and workspace layout

Validation

• cargo pr-check
• npm run build from docs/

UI display logic

• No new command action was added; the preference uses the property catalog and is searchable in the command palette.
• Status bar visibility changes only through an explicit user preference or its persisted startup value.
• No background event changes the layout or closes a panel.
• No new empty panel or region was introduced.
• Docs updated in docs/ in English and Simplified Chinese.