Add workspace health status with error counts and error message to expanded workspace cards
MR: Pending
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## Description
As part of our [new designs for Workspaces](https://gitlab.com/groups/gitlab-org/-/epics/18674), we need to display workspace health status with error information in the expanded workspace cards so that users can quickly identify and troubleshoot workspace issues.
## Visual Changes
{width=978 height=85}
## Acceptance criteria
- [ ] Add `healthStatus` field definition and resolver to workspace GraphQL type
- [ ] Backend returns error count and recent error messages from stored workspace errors
- [ ] Add "Health" section to expanded workspace cards with appropriate health icon
- [ ] Display error count when errors are present
- [ ] Show truncated error message preview
- [ ] Include three-dot menu button for expanding full error details
- [ ] Show healthy status if no errors
## Implementation plan
**Backend:**
- Add `healthStatus` field definition to workspace GraphQL type
- Implement resolver method that retrieves stored workspace errors
- Return error count and recent error messages from existing error storage
**Frontend:**
- Update GraphQL query to include `healthStatus` field from workspace type
- Add health information section to expanded workspace card component
- Display error count and truncated error message as shown in designs
- Implement three-dot menu for expanding full error details
## Technical Notes
- **Dependency:** Relies on workspace error logging architecture from https://gitlab.com/gitlab-org/gitlab/-/issues/552638+s
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