feat(chat): add configurable user message direction and bubble layout

[lesj0610]

Summary

• add a Chat settings control for user message direction with a one-click ltr/rtl toggle
• apply user-message alignment and bubble presentation updates across the main, shared, and search message renderers
• keep localization changes limited to English per repo guidance
• add a focused frontend test for the new setting

Change Type

• New feature (non-breaking change which adds functionality)
• Bug fix (non-breaking change which fixes an issue)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• Translation update

Testing

• npx eslint client/src/components/Nav/SettingsTabs/Chat/UserChatDirection.tsx client/src/components/Nav/SettingsTabs/Chat/UserChatDirection.spec.tsx client/src/components/Nav/SettingsTabs/Chat/Chat.tsx client/src/components/Chat/Messages/Content/MessageContent.tsx client/src/components/Chat/Messages/Content/Parts/Text.tsx client/src/components/Chat/Messages/Content/SearchContent.tsx client/src/components/Chat/Messages/MessageParts.tsx client/src/components/Chat/Messages/SearchMessage.tsx client/src/components/Chat/Messages/ui/MessageRender.tsx client/src/components/Messages/ContentRender.tsx client/src/store/settings.ts
• cd client && NODE_ENV=development npx jest --runInBand src/components/Nav/SettingsTabs/Chat/UserChatDirection.spec.tsx
• npm run frontend

Test Configuration:

• Node.js v24.13.0

Checklist

• My code adheres to this project's style guidelines
• I have performed a self-review of my own code
• I have commented in any complex areas of my code
• I have made pertinent documentation changes
• My changes do not introduce new warnings
• I have written tests demonstrating that my changes are effective or that my feature works
• Local unit tests pass with my changes
• Any changes dependent on mine have been merged and published in downstream modules.
• A pull request for updating the documentation has been submitted.