## Summary
Implements billing infrastructure for team workspaces, separate from
legacy personal billing.
## Changes
- **Billing abstraction**: New `useBillingContext` composable that
switches between legacy (personal) and workspace billing based on
context
- **Workspace subscription flows**: Pricing tables, plan transitions,
cancellation dialogs, and payment preview components for workspace
billing
- **Top-up credits**: Workspace-specific top-up dialog with polling for
payment confirmation
- **Workspace API**: Extended with billing endpoints (subscriptions,
invoices, payment methods, credits top-up)
- **Workspace switcher**: Now displays tier badges for each workspace
- **Subscribe polling**: Added polling mechanisms
(`useSubscribePolling`, `useTopupPolling`) for async payment flows
## Review Focus
- Billing flow correctness for workspace vs legacy contexts
- Polling timeout and error handling in payment flows
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8508-Feat-workspaces-6-billing-2f96d73d365081f69f65c1ddf369010d)
by [Unito](https://www.unito.io)
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
* basic about page
* Remove frontend version from setting dialog header
* Style about page
* basic system stats
* Basic styling
* Reword
* Format memory amount
