fix: await abortTask in cancelTask to prevent content loss

[roomote]

Related GitHub Issue

Closes: #10093

Description

This PR attempts to address Issue #10093 where canceling a task during an API request causes content loss.

Root Cause: In cancelTask(), task.abortTask() was called without await. The abortTask() method saves messages to disk asynchronously, but since it was not awaited, createTaskWithHistoryItem() would fetch the history before the messages were persisted.

Fix: Added await to the task.abortTask() call to ensure messages are properly saved to disk before attempting to rehydrate the task from history.

Test Procedure

1. Ran existing tests:
   • ClineProvider.spec.ts - All 99 tests pass
   • ClineProvider.flicker-free-cancel.spec.ts - All 4 tests pass
2. Manual testing steps:
   • Start a new task with any prompt
   • Wait for the API request to begin streaming
   • Click the "Cancel" button while streaming is in progress
   • Verify that the task retains conversation history up to the point of cancellation

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Testing: New and/or updated tests have been added to cover my changes (if applicable).
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

N/A - This is a backend fix with no UI changes.

Documentation Updates

• No documentation updates are required.

Additional Notes

Feedback and guidance are welcome.

[roomote]

Rooviewer   See task on Roo Cloud

Reviewed this PR - no issues found.

The fix correctly addresses the race condition in cancelTask() where messages weren't being persisted before rehydration. Adding await to task.abortTask() ensures saveClineMessages() completes before createTaskWithHistoryItem() reads from disk.

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