poc: new dialog system usage example

[maxy-shpfy]

Description

Added a test dialog component to demonstrate dialog functionality. The implementation includes:

• A new TestDialogButton component that opens a demo dialog
• A reusable TestDialog component that shows how to pass data back to the parent
• A useConfirmationDialog hook for creating nested confirmation dialogs
• Integration of the test button in the Pipeline Details view

The dialog system supports typed results, nested dialogs, and proper error handling for dialog cancellation.

Test Instructions

Screen Recording 2025-12-06 at 5.33.55 PM.mov (uploaded via Graphite)

1. Navigate to the Pipeline Details view
2. Click the "Open Test Dialog" button
3. Test the dialog functionality including:
   • Modifying the message text
   • Opening a nested confirmation dialog
   • Canceling and confirming dialogs
   • Observing toast notifications with dialog results

Additional Comments

This implementation demonstrates the pattern for creating and using dialogs throughout the application. The dialog system handles stacking, typed results, and proper cancellation flows.

[maxy-shpfy]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• poc: new dialog system usage example #1496 👈 (View in Graphite)
• poc: create dialog stackable system compatible with router and promises #1495
• master

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