fix: restore X button during save/reject prompts (#6865)

[roomote]

Description

This PR fixes issue #6865 where the X button (stop/close task button) was missing when the UI was prompting users to Save/Reject changes.

Problem

Users reported that they could not stop or terminate tasks when prompted with Save/Reject buttons. The X button was only visible during streaming operations but disappeared during approval prompts, preventing users from canceling tasks when:

• The LLM was making no useful progress
• Users were satisfied with partial changes
• They wanted to stop without completing the full reasoning process

Solution

Added a dedicated stop/close button (X icon) that remains visible when approval buttons are shown. The button:

• Appears as an icon button next to the approval buttons
• Allows users to terminate the current task at any time
• Uses the existing startNewTask() function to properly clean up the task
• Is styled consistently with other UI elements

Changes Made

• Modified ChatView.tsx to add a stop/close button when enableButtons is true and primaryButtonText exists
• The button is only shown during non-streaming approval states (Save/Reject, Approve/Reject, etc.)
• Uses the codicon-x icon for consistency with VS Code UI patterns

Testing

• ✅ All existing tests pass
• ✅ Linting passes with no warnings
• ✅ Type checking passes
• ✅ Manually tested the button appears during save/reject prompts
• ✅ Button successfully terminates the task when clicked

Screenshots

The X button now appears during save/reject prompts, allowing users to stop the task:

• Button is visible alongside Save/Reject buttons
• Maintains consistent styling with other UI elements

Fixes #6865

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Important

Adds a stop/close button in ChatView.tsx during save/reject prompts to allow task termination, addressing issue #6865.

• Behavior:
  • Adds a stop/close button (X icon) in ChatView.tsx during save/reject prompts when enableButtons is true and primaryButtonText exists.
  • Button allows task termination using startNewTask() function.
  • Button is styled with codicon-x for consistency with VS Code UI.
• Testing:
  • Manually tested button appearance and functionality during save/reject prompts.
  • All existing tests, linting, and type checking pass.

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[roomote]

Reviewing my own code because apparently I trust no one, not even myself.

[roomote]

Is this condition intentional? The logic checks for (secondaryButtonText || isStreaming) but then immediately requires !isStreaming, which effectively simplifies to just secondaryButtonText && !isStreaming. Could we simplify this for clarity?

[roomote]

The outer condition already ensures isStreaming is true, so this inner check isStreaming && !didClickCancel could be simplified to just !didClickCancel. Is there a reason for the redundant check?

[roomote]

Minor styling inconsistency: This button uses className="ml-2" while other buttons in this section use ml-[6px]. Consider using consistent spacing for visual harmony.

[roomote]

Consider adding an aria-label attribute for better accessibility. Screen readers would benefit from a descriptive label like aria-label="Close task" since the button only contains an icon.