Redesign options workspace UX

[bartekplus]

Summary

• redesign the options page into a unified workspace with sidebar navigation, search, denser card layouts, and consistent custom-panel rendering
• rebuild Languages, Snippets & Dictionary, Sites, Appearance, Data & Diagnostics, About, Essentials, and Grammar around the new workspace model while preserving existing settings keys and runtime behavior
• improve localization, appearance-theme compatibility, cross-panel reactivity, site profile editing UX, and targeted regression coverage for the redesigned options flows

Testing

• bun run lint
• bun run format:check
• bun run test
• bun run test:e2e
• bun run check:e2e:coverage

[bartekplus]

Updated the branch with a follow-up refinement:\n\n- now renders as a full-width card\n- stays as a separate card below it\n- no longer renders as a double-nested container\n- removed duplicate predictor debug description copy\n\nLocal verification:\n- bun test v1.3.10 (30e609e0)\n- \n- Checking formatting...
All matched files use Prettier code style!

[bartekplus]

Updated the branch with a follow-up Data & Diagnostics refinement:

• Productivity Dashboard now renders as a full-width card
• Configuration Data stays as a separate card below it
• Predictor Debug (Dev) no longer renders as a double-nested container
• removed duplicate predictor debug description copy

Local verification:

• bun test tests/optionsWorkspacePanels.test.ts
• bun run lint
• bun run format:check