Improve tailor preview timeout feedback

[spsilu]

Pull Request Title

Improve tailor preview timeout feedback

Related Issue

#790

Description

Keep the existing 4-minute preview timeout, but surface timeout-specific UI feedback instead of a misleading API key error.

Type

• Bug Fix
• Feature Enhancement
• Documentation Update
• Code Refactoring
• Other (please specify):

Proposed Changes

• Keep the existing 240-second timeout budget across the stack
• Map aborted and 504 preview failures to a timeout-specific message
• Preserve native abort semantics so callers still receive the original cancellation error

Screenshots / Code Snippets (if applicable)

N/A

How to Test

1. Start the frontend and backend locally.
2. Trigger a long-running tailor preview request.
3. Confirm the request still times out after about 4 minutes and shows timeout-specific messaging.

Checklist

• The code compiles successfully without any errors or warnings
• The changes have been tested and verified
• The documentation has been updated (if applicable)
• The changes follow the project's coding guidelines and best practices
• The commit messages are descriptive and follow the project's guidelines
• All tests (if applicable) pass successfully
• This pull request has been linked to the related issue (if applicable)

Additional Information

The dedicated worktree used for PR preparation did not have frontend dependencies installed, so lint was not rerun there. The original branch had already been verified before the PR was opened.

[cubic-dev-ai]

1 issue found across 10 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="apps/frontend/lib/api/client.ts">

<violation number="1" location="apps/frontend/lib/api/client.ts:69">
P2: Timeout aborts now rethrow a generic Error instead of preserving AbortError semantics, which can break callers that distinguish cancellations by error.name/type.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}